Solve for y
y=-5
y=2
Graph
Share
Copied to clipboard
y\times 6-\left(y+2\right)\times 5=-y\left(y+2\right)
Variable y cannot be equal to any of the values -2,0 since division by zero is not defined. Multiply both sides of the equation by y\left(y+2\right), the least common multiple of 2+y,y.
y\times 6-\left(5y+10\right)=-y\left(y+2\right)
Use the distributive property to multiply y+2 by 5.
y\times 6-5y-10=-y\left(y+2\right)
To find the opposite of 5y+10, find the opposite of each term.
y-10=-y\left(y+2\right)
Combine y\times 6 and -5y to get y.
y-10=-y^{2}-2y
Use the distributive property to multiply -y by y+2.
y-10+y^{2}=-2y
Add y^{2} to both sides.
y-10+y^{2}+2y=0
Add 2y to both sides.
3y-10+y^{2}=0
Combine y and 2y to get 3y.
y^{2}+3y-10=0
Rearrange the polynomial to put it in standard form. Place the terms in order from highest to lowest power.
a+b=3 ab=-10
To solve the equation, factor y^{2}+3y-10 using formula y^{2}+\left(a+b\right)y+ab=\left(y+a\right)\left(y+b\right). To find a and b, set up a system to be solved.
-1,10 -2,5
Since ab is negative, a and b have the opposite signs. Since a+b is positive, the positive number has greater absolute value than the negative. List all such integer pairs that give product -10.
-1+10=9 -2+5=3
Calculate the sum for each pair.
a=-2 b=5
The solution is the pair that gives sum 3.
\left(y-2\right)\left(y+5\right)
Rewrite factored expression \left(y+a\right)\left(y+b\right) using the obtained values.
y=2 y=-5
To find equation solutions, solve y-2=0 and y+5=0.
y\times 6-\left(y+2\right)\times 5=-y\left(y+2\right)
Variable y cannot be equal to any of the values -2,0 since division by zero is not defined. Multiply both sides of the equation by y\left(y+2\right), the least common multiple of 2+y,y.
y\times 6-\left(5y+10\right)=-y\left(y+2\right)
Use the distributive property to multiply y+2 by 5.
y\times 6-5y-10=-y\left(y+2\right)
To find the opposite of 5y+10, find the opposite of each term.
y-10=-y\left(y+2\right)
Combine y\times 6 and -5y to get y.
y-10=-y^{2}-2y
Use the distributive property to multiply -y by y+2.
y-10+y^{2}=-2y
Add y^{2} to both sides.
y-10+y^{2}+2y=0
Add 2y to both sides.
3y-10+y^{2}=0
Combine y and 2y to get 3y.
y^{2}+3y-10=0
Rearrange the polynomial to put it in standard form. Place the terms in order from highest to lowest power.
a+b=3 ab=1\left(-10\right)=-10
To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as y^{2}+ay+by-10. To find a and b, set up a system to be solved.
-1,10 -2,5
Since ab is negative, a and b have the opposite signs. Since a+b is positive, the positive number has greater absolute value than the negative. List all such integer pairs that give product -10.
-1+10=9 -2+5=3
Calculate the sum for each pair.
a=-2 b=5
The solution is the pair that gives sum 3.
\left(y^{2}-2y\right)+\left(5y-10\right)
Rewrite y^{2}+3y-10 as \left(y^{2}-2y\right)+\left(5y-10\right).
y\left(y-2\right)+5\left(y-2\right)
Factor out y in the first and 5 in the second group.
\left(y-2\right)\left(y+5\right)
Factor out common term y-2 by using distributive property.
y=2 y=-5
To find equation solutions, solve y-2=0 and y+5=0.
y\times 6-\left(y+2\right)\times 5=-y\left(y+2\right)
Variable y cannot be equal to any of the values -2,0 since division by zero is not defined. Multiply both sides of the equation by y\left(y+2\right), the least common multiple of 2+y,y.
y\times 6-\left(5y+10\right)=-y\left(y+2\right)
Use the distributive property to multiply y+2 by 5.
y\times 6-5y-10=-y\left(y+2\right)
To find the opposite of 5y+10, find the opposite of each term.
y-10=-y\left(y+2\right)
Combine y\times 6 and -5y to get y.
y-10=-y^{2}-2y
Use the distributive property to multiply -y by y+2.
y-10+y^{2}=-2y
Add y^{2} to both sides.
y-10+y^{2}+2y=0
Add 2y to both sides.
3y-10+y^{2}=0
Combine y and 2y to get 3y.
y^{2}+3y-10=0
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.
y=\frac{-3±\sqrt{3^{2}-4\left(-10\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 3 for b, and -10 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
y=\frac{-3±\sqrt{9-4\left(-10\right)}}{2}
Square 3.
y=\frac{-3±\sqrt{9+40}}{2}
Multiply -4 times -10.
y=\frac{-3±\sqrt{49}}{2}
Add 9 to 40.
y=\frac{-3±7}{2}
Take the square root of 49.
y=\frac{4}{2}
Now solve the equation y=\frac{-3±7}{2} when ± is plus. Add -3 to 7.
y=2
Divide 4 by 2.
y=-\frac{10}{2}
Now solve the equation y=\frac{-3±7}{2} when ± is minus. Subtract 7 from -3.
y=-5
Divide -10 by 2.
y=2 y=-5
The equation is now solved.
y\times 6-\left(y+2\right)\times 5=-y\left(y+2\right)
Variable y cannot be equal to any of the values -2,0 since division by zero is not defined. Multiply both sides of the equation by y\left(y+2\right), the least common multiple of 2+y,y.
y\times 6-\left(5y+10\right)=-y\left(y+2\right)
Use the distributive property to multiply y+2 by 5.
y\times 6-5y-10=-y\left(y+2\right)
To find the opposite of 5y+10, find the opposite of each term.
y-10=-y\left(y+2\right)
Combine y\times 6 and -5y to get y.
y-10=-y^{2}-2y
Use the distributive property to multiply -y by y+2.
y-10+y^{2}=-2y
Add y^{2} to both sides.
y-10+y^{2}+2y=0
Add 2y to both sides.
3y-10+y^{2}=0
Combine y and 2y to get 3y.
3y+y^{2}=10
Add 10 to both sides. Anything plus zero gives itself.
y^{2}+3y=10
Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.
y^{2}+3y+\left(\frac{3}{2}\right)^{2}=10+\left(\frac{3}{2}\right)^{2}
Divide 3, the coefficient of the x term, by 2 to get \frac{3}{2}. Then add the square of \frac{3}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
y^{2}+3y+\frac{9}{4}=10+\frac{9}{4}
Square \frac{3}{2} by squaring both the numerator and the denominator of the fraction.
y^{2}+3y+\frac{9}{4}=\frac{49}{4}
Add 10 to \frac{9}{4}.
\left(y+\frac{3}{2}\right)^{2}=\frac{49}{4}
Factor y^{2}+3y+\frac{9}{4}. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.
\sqrt{\left(y+\frac{3}{2}\right)^{2}}=\sqrt{\frac{49}{4}}
Take the square root of both sides of the equation.
y+\frac{3}{2}=\frac{7}{2} y+\frac{3}{2}=-\frac{7}{2}
Simplify.
y=2 y=-5
Subtract \frac{3}{2} from both sides of the equation.
Examples
Quadratic equation
{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}