How do you solve these 2 equations?
$$xy = 1/6$$
$$y+x = 5xy$$
I tried solving them using all methods - substitution, elimination and graphing - but can't get the solutions
systems-of-equations quadratics symmetric-polynomials
|
show 1 more comment
$$xy = 1/6$$
$$y+x = 5xy$$
I tried solving them using all methods - substitution, elimination and graphing - but can't get the solutions
systems-of-equations quadratics symmetric-polynomials
What were "all those methods" that you tried?
– Parcly Taxel
Nov 18 '18 at 6:07
Substitution, elimination and graphing.
– Jullian Santos
Nov 18 '18 at 6:11
Take the first equation and insert it into the second
– Fakemistake
Nov 18 '18 at 6:11
Actually I can't use the graphing so what I meant was substitution and elimination.
– Jullian Santos
Nov 18 '18 at 6:12
Remember if the amount of variables and amount of equations are equal, you can always solve that system of equations. Just substitute the value of any one variable from one equation in another.
– PradyumanDixit
Nov 18 '18 at 6:12
|
show 1 more comment
$$xy = 1/6$$
$$y+x = 5xy$$
I tried solving them using all methods - substitution, elimination and graphing - but can't get the solutions
systems-of-equations quadratics symmetric-polynomials
$$xy = 1/6$$
$$y+x = 5xy$$
I tried solving them using all methods - substitution, elimination and graphing - but can't get the solutions
systems-of-equations quadratics symmetric-polynomials
systems-of-equations quadratics symmetric-polynomials
edited Nov 23 '18 at 11:59
Harry Peter
5,46111439
5,46111439
asked Nov 18 '18 at 6:06
Jullian SantosJullian Santos
6
6
What were "all those methods" that you tried?
– Parcly Taxel
Nov 18 '18 at 6:07
Substitution, elimination and graphing.
– Jullian Santos
Nov 18 '18 at 6:11
Take the first equation and insert it into the second
– Fakemistake
Nov 18 '18 at 6:11
Actually I can't use the graphing so what I meant was substitution and elimination.
– Jullian Santos
Nov 18 '18 at 6:12
Remember if the amount of variables and amount of equations are equal, you can always solve that system of equations. Just substitute the value of any one variable from one equation in another.
– PradyumanDixit
Nov 18 '18 at 6:12
|
show 1 more comment
What were "all those methods" that you tried?
– Parcly Taxel
Nov 18 '18 at 6:07
Substitution, elimination and graphing.
– Jullian Santos
Nov 18 '18 at 6:11
Take the first equation and insert it into the second
– Fakemistake
Nov 18 '18 at 6:11
Actually I can't use the graphing so what I meant was substitution and elimination.
– Jullian Santos
Nov 18 '18 at 6:12
Remember if the amount of variables and amount of equations are equal, you can always solve that system of equations. Just substitute the value of any one variable from one equation in another.
– PradyumanDixit
Nov 18 '18 at 6:12
What were "all those methods" that you tried?
– Parcly Taxel
Nov 18 '18 at 6:07
What were "all those methods" that you tried?
– Parcly Taxel
Nov 18 '18 at 6:07
Substitution, elimination and graphing.
– Jullian Santos
Nov 18 '18 at 6:11
Substitution, elimination and graphing.
– Jullian Santos
Nov 18 '18 at 6:11
Take the first equation and insert it into the second
– Fakemistake
Nov 18 '18 at 6:11
Take the first equation and insert it into the second
– Fakemistake
Nov 18 '18 at 6:11
Actually I can't use the graphing so what I meant was substitution and elimination.
– Jullian Santos
Nov 18 '18 at 6:12
Actually I can't use the graphing so what I meant was substitution and elimination.
– Jullian Santos
Nov 18 '18 at 6:12
Remember if the amount of variables and amount of equations are equal, you can always solve that system of equations. Just substitute the value of any one variable from one equation in another.
– PradyumanDixit
Nov 18 '18 at 6:12
Remember if the amount of variables and amount of equations are equal, you can always solve that system of equations. Just substitute the value of any one variable from one equation in another.
– PradyumanDixit
Nov 18 '18 at 6:12
|
show 1 more comment
3 Answers
3
active
oldest
votes
You can solve this equation by using substitution of variables.
Using the first equation $xy=1/6$, we can rewrite it as $y=frac1{6x}$.
Plugging this in to the second equation, we get $$x+frac1{6x}=5frac{x}{6x}$$
Simplify the right-hand side to $frac56$ and multiply both sides by $x$ to obtain
$$x^2+frac16=frac56x to x^2-frac56x+frac16=0$$
Using the quadratic formula, we now have $$x=frac{frac56 pm sqrt{frac{25}{36}-frac46}}{2}=frac5{12} pm frac12sqrt{frac1{36}}=frac5{12} pm frac1{12}$$
Our solutions for $x$ are $frac13$ and $frac12$. Using $y=frac1{6x}$, we get the coordinate pairs to be $(frac13,frac12)$ and $(frac12,frac13)$.
2
In the quadratic equation, it's easier to compute if we just first multiply both sides with $6$ to get $6x^2 -5x +1=0$, and get only integers to compute with. The determinant becomes $(-5)^2 - 4cdot 6 = 1$ so we get a nice result.
– Henno Brandsma
Nov 18 '18 at 6:27
Thanks for the answer!
– Jullian Santos
Nov 18 '18 at 6:27
add a comment |
1) Substitute $;xy=frac{1}{6}$ into the 2nd equation to get $;x+y=frac{5}{6}$
2) Solving $;xy=frac{1}{6}$ and $;x+y=frac{5}{6};$ is equivalent to finding the zeros of the function $f(z)=z^2+frac{5}{6}z+frac{1}{6}=0,;$ so using the quadratic formula, $;x=-frac{1}{3};text{and}; y=-frac{1}{2};$ or $;y=-frac{1}{3};text{and};x=-frac{1}{2}.$
Would you check your quadratic equation? The signs.
– user376343
Dec 29 '18 at 10:00
add a comment |
begin{array}{c}
xy = frac 16 \
x + y = 5xy = frac 56
end{array}
Let $x = frac{5}{12} + t$ and $y = frac{5}{12}-t$. Then $x+y=frac 56$.
begin{align}
xy &= frac 16 \
bigg(frac{5}{12} + t bigg) bigg(frac{5}{12} - tbigg) &= frac 16 \
frac{25}{144} - t^2 &= frac{24}{144} \
t^2 &= frac{1}{144} \
t &= pm frac{1}{12} \
end{align}
$frac{5}{12} + frac{1}{12} = frac 12$ and $frac{5}{12} - frac{1}{12} = frac 13$
So $(x,y) = left{big(frac 12,frac 13 big),big(frac 13,frac 12 big)right}$
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
You can solve this equation by using substitution of variables.
Using the first equation $xy=1/6$, we can rewrite it as $y=frac1{6x}$.
Plugging this in to the second equation, we get $$x+frac1{6x}=5frac{x}{6x}$$
Simplify the right-hand side to $frac56$ and multiply both sides by $x$ to obtain
$$x^2+frac16=frac56x to x^2-frac56x+frac16=0$$
Using the quadratic formula, we now have $$x=frac{frac56 pm sqrt{frac{25}{36}-frac46}}{2}=frac5{12} pm frac12sqrt{frac1{36}}=frac5{12} pm frac1{12}$$
Our solutions for $x$ are $frac13$ and $frac12$. Using $y=frac1{6x}$, we get the coordinate pairs to be $(frac13,frac12)$ and $(frac12,frac13)$.
2
In the quadratic equation, it's easier to compute if we just first multiply both sides with $6$ to get $6x^2 -5x +1=0$, and get only integers to compute with. The determinant becomes $(-5)^2 - 4cdot 6 = 1$ so we get a nice result.
– Henno Brandsma
Nov 18 '18 at 6:27
Thanks for the answer!
– Jullian Santos
Nov 18 '18 at 6:27
add a comment |
You can solve this equation by using substitution of variables.
Using the first equation $xy=1/6$, we can rewrite it as $y=frac1{6x}$.
Plugging this in to the second equation, we get $$x+frac1{6x}=5frac{x}{6x}$$
Simplify the right-hand side to $frac56$ and multiply both sides by $x$ to obtain
$$x^2+frac16=frac56x to x^2-frac56x+frac16=0$$
Using the quadratic formula, we now have $$x=frac{frac56 pm sqrt{frac{25}{36}-frac46}}{2}=frac5{12} pm frac12sqrt{frac1{36}}=frac5{12} pm frac1{12}$$
Our solutions for $x$ are $frac13$ and $frac12$. Using $y=frac1{6x}$, we get the coordinate pairs to be $(frac13,frac12)$ and $(frac12,frac13)$.
2
In the quadratic equation, it's easier to compute if we just first multiply both sides with $6$ to get $6x^2 -5x +1=0$, and get only integers to compute with. The determinant becomes $(-5)^2 - 4cdot 6 = 1$ so we get a nice result.
– Henno Brandsma
Nov 18 '18 at 6:27
Thanks for the answer!
– Jullian Santos
Nov 18 '18 at 6:27
add a comment |
You can solve this equation by using substitution of variables.
Using the first equation $xy=1/6$, we can rewrite it as $y=frac1{6x}$.
Plugging this in to the second equation, we get $$x+frac1{6x}=5frac{x}{6x}$$
Simplify the right-hand side to $frac56$ and multiply both sides by $x$ to obtain
$$x^2+frac16=frac56x to x^2-frac56x+frac16=0$$
Using the quadratic formula, we now have $$x=frac{frac56 pm sqrt{frac{25}{36}-frac46}}{2}=frac5{12} pm frac12sqrt{frac1{36}}=frac5{12} pm frac1{12}$$
Our solutions for $x$ are $frac13$ and $frac12$. Using $y=frac1{6x}$, we get the coordinate pairs to be $(frac13,frac12)$ and $(frac12,frac13)$.
You can solve this equation by using substitution of variables.
Using the first equation $xy=1/6$, we can rewrite it as $y=frac1{6x}$.
Plugging this in to the second equation, we get $$x+frac1{6x}=5frac{x}{6x}$$
Simplify the right-hand side to $frac56$ and multiply both sides by $x$ to obtain
$$x^2+frac16=frac56x to x^2-frac56x+frac16=0$$
Using the quadratic formula, we now have $$x=frac{frac56 pm sqrt{frac{25}{36}-frac46}}{2}=frac5{12} pm frac12sqrt{frac1{36}}=frac5{12} pm frac1{12}$$
Our solutions for $x$ are $frac13$ and $frac12$. Using $y=frac1{6x}$, we get the coordinate pairs to be $(frac13,frac12)$ and $(frac12,frac13)$.
answered Nov 18 '18 at 6:20
Christopher MarleyChristopher Marley
1,020115
1,020115
2
In the quadratic equation, it's easier to compute if we just first multiply both sides with $6$ to get $6x^2 -5x +1=0$, and get only integers to compute with. The determinant becomes $(-5)^2 - 4cdot 6 = 1$ so we get a nice result.
– Henno Brandsma
Nov 18 '18 at 6:27
Thanks for the answer!
– Jullian Santos
Nov 18 '18 at 6:27
add a comment |
2
In the quadratic equation, it's easier to compute if we just first multiply both sides with $6$ to get $6x^2 -5x +1=0$, and get only integers to compute with. The determinant becomes $(-5)^2 - 4cdot 6 = 1$ so we get a nice result.
– Henno Brandsma
Nov 18 '18 at 6:27
Thanks for the answer!
– Jullian Santos
Nov 18 '18 at 6:27
2
2
In the quadratic equation, it's easier to compute if we just first multiply both sides with $6$ to get $6x^2 -5x +1=0$, and get only integers to compute with. The determinant becomes $(-5)^2 - 4cdot 6 = 1$ so we get a nice result.
– Henno Brandsma
Nov 18 '18 at 6:27
In the quadratic equation, it's easier to compute if we just first multiply both sides with $6$ to get $6x^2 -5x +1=0$, and get only integers to compute with. The determinant becomes $(-5)^2 - 4cdot 6 = 1$ so we get a nice result.
– Henno Brandsma
Nov 18 '18 at 6:27
Thanks for the answer!
– Jullian Santos
Nov 18 '18 at 6:27
Thanks for the answer!
– Jullian Santos
Nov 18 '18 at 6:27
add a comment |
1) Substitute $;xy=frac{1}{6}$ into the 2nd equation to get $;x+y=frac{5}{6}$
2) Solving $;xy=frac{1}{6}$ and $;x+y=frac{5}{6};$ is equivalent to finding the zeros of the function $f(z)=z^2+frac{5}{6}z+frac{1}{6}=0,;$ so using the quadratic formula, $;x=-frac{1}{3};text{and}; y=-frac{1}{2};$ or $;y=-frac{1}{3};text{and};x=-frac{1}{2}.$
Would you check your quadratic equation? The signs.
– user376343
Dec 29 '18 at 10:00
add a comment |
1) Substitute $;xy=frac{1}{6}$ into the 2nd equation to get $;x+y=frac{5}{6}$
2) Solving $;xy=frac{1}{6}$ and $;x+y=frac{5}{6};$ is equivalent to finding the zeros of the function $f(z)=z^2+frac{5}{6}z+frac{1}{6}=0,;$ so using the quadratic formula, $;x=-frac{1}{3};text{and}; y=-frac{1}{2};$ or $;y=-frac{1}{3};text{and};x=-frac{1}{2}.$
Would you check your quadratic equation? The signs.
– user376343
Dec 29 '18 at 10:00
add a comment |
1) Substitute $;xy=frac{1}{6}$ into the 2nd equation to get $;x+y=frac{5}{6}$
2) Solving $;xy=frac{1}{6}$ and $;x+y=frac{5}{6};$ is equivalent to finding the zeros of the function $f(z)=z^2+frac{5}{6}z+frac{1}{6}=0,;$ so using the quadratic formula, $;x=-frac{1}{3};text{and}; y=-frac{1}{2};$ or $;y=-frac{1}{3};text{and};x=-frac{1}{2}.$
1) Substitute $;xy=frac{1}{6}$ into the 2nd equation to get $;x+y=frac{5}{6}$
2) Solving $;xy=frac{1}{6}$ and $;x+y=frac{5}{6};$ is equivalent to finding the zeros of the function $f(z)=z^2+frac{5}{6}z+frac{1}{6}=0,;$ so using the quadratic formula, $;x=-frac{1}{3};text{and}; y=-frac{1}{2};$ or $;y=-frac{1}{3};text{and};x=-frac{1}{2}.$
edited Dec 29 '18 at 9:58
user376343
3,0032823
3,0032823
answered Nov 18 '18 at 6:23
Muchang BahngMuchang Bahng
663
663
Would you check your quadratic equation? The signs.
– user376343
Dec 29 '18 at 10:00
add a comment |
Would you check your quadratic equation? The signs.
– user376343
Dec 29 '18 at 10:00
Would you check your quadratic equation? The signs.
– user376343
Dec 29 '18 at 10:00
Would you check your quadratic equation? The signs.
– user376343
Dec 29 '18 at 10:00
add a comment |
begin{array}{c}
xy = frac 16 \
x + y = 5xy = frac 56
end{array}
Let $x = frac{5}{12} + t$ and $y = frac{5}{12}-t$. Then $x+y=frac 56$.
begin{align}
xy &= frac 16 \
bigg(frac{5}{12} + t bigg) bigg(frac{5}{12} - tbigg) &= frac 16 \
frac{25}{144} - t^2 &= frac{24}{144} \
t^2 &= frac{1}{144} \
t &= pm frac{1}{12} \
end{align}
$frac{5}{12} + frac{1}{12} = frac 12$ and $frac{5}{12} - frac{1}{12} = frac 13$
So $(x,y) = left{big(frac 12,frac 13 big),big(frac 13,frac 12 big)right}$
add a comment |
begin{array}{c}
xy = frac 16 \
x + y = 5xy = frac 56
end{array}
Let $x = frac{5}{12} + t$ and $y = frac{5}{12}-t$. Then $x+y=frac 56$.
begin{align}
xy &= frac 16 \
bigg(frac{5}{12} + t bigg) bigg(frac{5}{12} - tbigg) &= frac 16 \
frac{25}{144} - t^2 &= frac{24}{144} \
t^2 &= frac{1}{144} \
t &= pm frac{1}{12} \
end{align}
$frac{5}{12} + frac{1}{12} = frac 12$ and $frac{5}{12} - frac{1}{12} = frac 13$
So $(x,y) = left{big(frac 12,frac 13 big),big(frac 13,frac 12 big)right}$
add a comment |
begin{array}{c}
xy = frac 16 \
x + y = 5xy = frac 56
end{array}
Let $x = frac{5}{12} + t$ and $y = frac{5}{12}-t$. Then $x+y=frac 56$.
begin{align}
xy &= frac 16 \
bigg(frac{5}{12} + t bigg) bigg(frac{5}{12} - tbigg) &= frac 16 \
frac{25}{144} - t^2 &= frac{24}{144} \
t^2 &= frac{1}{144} \
t &= pm frac{1}{12} \
end{align}
$frac{5}{12} + frac{1}{12} = frac 12$ and $frac{5}{12} - frac{1}{12} = frac 13$
So $(x,y) = left{big(frac 12,frac 13 big),big(frac 13,frac 12 big)right}$
begin{array}{c}
xy = frac 16 \
x + y = 5xy = frac 56
end{array}
Let $x = frac{5}{12} + t$ and $y = frac{5}{12}-t$. Then $x+y=frac 56$.
begin{align}
xy &= frac 16 \
bigg(frac{5}{12} + t bigg) bigg(frac{5}{12} - tbigg) &= frac 16 \
frac{25}{144} - t^2 &= frac{24}{144} \
t^2 &= frac{1}{144} \
t &= pm frac{1}{12} \
end{align}
$frac{5}{12} + frac{1}{12} = frac 12$ and $frac{5}{12} - frac{1}{12} = frac 13$
So $(x,y) = left{big(frac 12,frac 13 big),big(frac 13,frac 12 big)right}$
edited Dec 30 '18 at 21:32
answered Dec 29 '18 at 10:36
steven gregorysteven gregory
17.7k32257
17.7k32257
add a comment |
add a comment |
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What were "all those methods" that you tried?
– Parcly Taxel
Nov 18 '18 at 6:07
Substitution, elimination and graphing.
– Jullian Santos
Nov 18 '18 at 6:11
Take the first equation and insert it into the second
– Fakemistake
Nov 18 '18 at 6:11
Actually I can't use the graphing so what I meant was substitution and elimination.
– Jullian Santos
Nov 18 '18 at 6:12
Remember if the amount of variables and amount of equations are equal, you can always solve that system of equations. Just substitute the value of any one variable from one equation in another.
– PradyumanDixit
Nov 18 '18 at 6:12