2(y+7)(-y+8)=0

Solution for 2(y+7)(-y+8)=0 equation:

2(y+7)(-y+8)=0

We add all the numbers together, and all the variables

2(y+7)(-1y+8)=0

We multiply parentheses ..

2(-1y^2+8y-7y+56)=0

We multiply parentheses

-2y^2+16y-14y+112=0

We add all the numbers together, and all the variables

-2y^2+2y+112=0

a = -2; b = 2; c = +112;
Δ = b2-4ac
Δ = 22-4·(-2)·112
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-30}{2*-2}=\frac{-32}{-4}
=+8
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+30}{2*-2}=\frac{28}{-4}
=-7
$