(x+20)(x-8)=-7x

Solution for (x+20)(x-8)=-7x equation:

(x+20)(x-8)=-7x

We move all terms to the left:

(x+20)(x-8)-(-7x)=0

We get rid of parentheses

(x+20)(x-8)+7x=0

We multiply parentheses ..

(+x^2-8x+20x-160)+7x=0

We get rid of parentheses

x^2-8x+20x+7x-160=0

We add all the numbers together, and all the variables

x^2+19x-160=0

a = 1; b = 19; c = -160;
Δ = b2-4ac
Δ = 192-4·1·(-160)
Δ = 1001
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-\sqrt{1001}}{2*1}=\frac{-19-\sqrt{1001}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+\sqrt{1001}}{2*1}=\frac{-19+\sqrt{1001}}{2}
$