(X+4)(2x-2)=0

Solution for (X+4)(2x-2)=0 equation:

(X+4)(2X-2)=0

We multiply parentheses ..

(+2X^2-2X+8X-8)=0

We get rid of parentheses

2X^2-2X+8X-8=0

We add all the numbers together, and all the variables

2X^2+6X-8=0

a = 2; b = 6; c = -8;
Δ = b2-4ac
Δ = 62-4·2·(-8)
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-10}{2*2}=\frac{-16}{4}
=-4
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+10}{2*2}=\frac{4}{4}
=1
$