(2x-8)(x+5)=140

Solution for (2x-8)(x+5)=140 equation:

(2x-8)(x+5)=140

We move all terms to the left:

(2x-8)(x+5)-(140)=0

We multiply parentheses ..

(+2x^2+10x-8x-40)-140=0

We get rid of parentheses

2x^2+10x-8x-40-140=0

We add all the numbers together, and all the variables

2x^2+2x-180=0

a = 2; b = 2; c = -180;
Δ = b2-4ac
Δ = 22-4·2·(-180)
Δ = 1444
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1444}=38$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-38}{2*2}=\frac{-40}{4}
=-10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+38}{2*2}=\frac{36}{4}
=9
$