(5w+5)(2w+8)=90

Solution for (5w+5)(2w+8)=90 equation:

(5w+5)(2w+8)=90

We move all terms to the left:

(5w+5)(2w+8)-(90)=0

We multiply parentheses ..

(+10w^2+40w+10w+40)-90=0

We get rid of parentheses

10w^2+40w+10w+40-90=0

We add all the numbers together, and all the variables

10w^2+50w-50=0

a = 10; b = 50; c = -50;
Δ = b2-4ac
Δ = 502-4·10·(-50)
Δ = 4500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{4500}=\sqrt{900*5}=\sqrt{900}*\sqrt{5}=30\sqrt{5}$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-30\sqrt{5}}{2*10}=\frac{-50-30\sqrt{5}}{20}
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+30\sqrt{5}}{2*10}=\frac{-50+30\sqrt{5}}{20}
$