Solve for y
y=-1
y=\frac{2}{5}=0.4
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\left(3y+6\right)\left(y+2\right)-\left(3y-6\right)\times 2=-7\left(y-2\right)\left(y+2\right)
Variable y cannot be equal to any of the values -2,2 since division by zero is not defined. Multiply both sides of the equation by 3\left(y-2\right)\left(y+2\right), the least common multiple of y-2,y+2,3.
3y^{2}+12y+12-\left(3y-6\right)\times 2=-7\left(y-2\right)\left(y+2\right)
Use the distributive property to multiply 3y+6 by y+2 and combine like terms.
3y^{2}+12y+12-\left(6y-12\right)=-7\left(y-2\right)\left(y+2\right)
Use the distributive property to multiply 3y-6 by 2.
3y^{2}+12y+12-6y+12=-7\left(y-2\right)\left(y+2\right)
To find the opposite of 6y-12, find the opposite of each term.
3y^{2}+6y+12+12=-7\left(y-2\right)\left(y+2\right)
Combine 12y and -6y to get 6y.
3y^{2}+6y+24=-7\left(y-2\right)\left(y+2\right)
Add 12 and 12 to get 24.
3y^{2}+6y+24=\left(-7y+14\right)\left(y+2\right)
Use the distributive property to multiply -7 by y-2.
3y^{2}+6y+24=-7y^{2}+28
Use the distributive property to multiply -7y+14 by y+2 and combine like terms.
3y^{2}+6y+24+7y^{2}=28
Add 7y^{2} to both sides.
10y^{2}+6y+24=28
Combine 3y^{2} and 7y^{2} to get 10y^{2}.
10y^{2}+6y+24-28=0
Subtract 28 from both sides.
10y^{2}+6y-4=0
Subtract 28 from 24 to get -4.
y=\frac{-6±\sqrt{6^{2}-4\times 10\left(-4\right)}}{2\times 10}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 10 for a, 6 for b, and -4 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
y=\frac{-6±\sqrt{36-4\times 10\left(-4\right)}}{2\times 10}
Square 6.
y=\frac{-6±\sqrt{36-40\left(-4\right)}}{2\times 10}
Multiply -4 times 10.
y=\frac{-6±\sqrt{36+160}}{2\times 10}
Multiply -40 times -4.
y=\frac{-6±\sqrt{196}}{2\times 10}
Add 36 to 160.
y=\frac{-6±14}{2\times 10}
Take the square root of 196.
y=\frac{-6±14}{20}
Multiply 2 times 10.
y=\frac{8}{20}
Now solve the equation y=\frac{-6±14}{20} when ± is plus. Add -6 to 14.
y=\frac{2}{5}
Reduce the fraction \frac{8}{20} to lowest terms by extracting and canceling out 4.
y=-\frac{20}{20}
Now solve the equation y=\frac{-6±14}{20} when ± is minus. Subtract 14 from -6.
y=-1
Divide -20 by 20.
y=\frac{2}{5} y=-1
The equation is now solved.
\left(3y+6\right)\left(y+2\right)-\left(3y-6\right)\times 2=-7\left(y-2\right)\left(y+2\right)
Variable y cannot be equal to any of the values -2,2 since division by zero is not defined. Multiply both sides of the equation by 3\left(y-2\right)\left(y+2\right), the least common multiple of y-2,y+2,3.
3y^{2}+12y+12-\left(3y-6\right)\times 2=-7\left(y-2\right)\left(y+2\right)
Use the distributive property to multiply 3y+6 by y+2 and combine like terms.
3y^{2}+12y+12-\left(6y-12\right)=-7\left(y-2\right)\left(y+2\right)
Use the distributive property to multiply 3y-6 by 2.
3y^{2}+12y+12-6y+12=-7\left(y-2\right)\left(y+2\right)
To find the opposite of 6y-12, find the opposite of each term.
3y^{2}+6y+12+12=-7\left(y-2\right)\left(y+2\right)
Combine 12y and -6y to get 6y.
3y^{2}+6y+24=-7\left(y-2\right)\left(y+2\right)
Add 12 and 12 to get 24.
3y^{2}+6y+24=\left(-7y+14\right)\left(y+2\right)
Use the distributive property to multiply -7 by y-2.
3y^{2}+6y+24=-7y^{2}+28
Use the distributive property to multiply -7y+14 by y+2 and combine like terms.
3y^{2}+6y+24+7y^{2}=28
Add 7y^{2} to both sides.
10y^{2}+6y+24=28
Combine 3y^{2} and 7y^{2} to get 10y^{2}.
10y^{2}+6y=28-24
Subtract 24 from both sides.
10y^{2}+6y=4
Subtract 24 from 28 to get 4.
\frac{10y^{2}+6y}{10}=\frac{4}{10}
Divide both sides by 10.
y^{2}+\frac{6}{10}y=\frac{4}{10}
Dividing by 10 undoes the multiplication by 10.
y^{2}+\frac{3}{5}y=\frac{4}{10}
Reduce the fraction \frac{6}{10} to lowest terms by extracting and canceling out 2.
y^{2}+\frac{3}{5}y=\frac{2}{5}
Reduce the fraction \frac{4}{10} to lowest terms by extracting and canceling out 2.
y^{2}+\frac{3}{5}y+\left(\frac{3}{10}\right)^{2}=\frac{2}{5}+\left(\frac{3}{10}\right)^{2}
Divide \frac{3}{5}, the coefficient of the x term, by 2 to get \frac{3}{10}. Then add the square of \frac{3}{10} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
y^{2}+\frac{3}{5}y+\frac{9}{100}=\frac{2}{5}+\frac{9}{100}
Square \frac{3}{10} by squaring both the numerator and the denominator of the fraction.
y^{2}+\frac{3}{5}y+\frac{9}{100}=\frac{49}{100}
Add \frac{2}{5} to \frac{9}{100} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
\left(y+\frac{3}{10}\right)^{2}=\frac{49}{100}
Factor y^{2}+\frac{3}{5}y+\frac{9}{100}. 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}{10}\right)^{2}}=\sqrt{\frac{49}{100}}
Take the square root of both sides of the equation.
y+\frac{3}{10}=\frac{7}{10} y+\frac{3}{10}=-\frac{7}{10}
Simplify.
y=\frac{2}{5} y=-1
Subtract \frac{3}{10} from both sides of the equation.
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{ x } ^ { 2 } - 4 x - 5 = 0
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4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
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699 * 533
Matrix
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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
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