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

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

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

We multiply parentheses ..

(+2w^2+8w-14w-56)=0

We get rid of parentheses

2w^2+8w-14w-56=0

We add all the numbers together, and all the variables

2w^2-6w-56=0

a = 2; b = -6; c = -56;
Δ = b2-4ac
Δ = -62-4·2·(-56)
Δ = 484
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{484}=22$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-22}{2*2}=\frac{-16}{4}
=-4
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+22}{2*2}=\frac{28}{4}
=7
$