A=(w+5)(2w)

Solution for A=(w+5)(2w) equation:

=(A+5)(2A)

We move all terms to the left:

-((A+5)(2A))=0


We calculate terms in parentheses: -((A+5)2A), so:

(A+5)2A

We multiply parentheses

2A^2+10A

Back to the equation:

-(2A^2+10A)


We get rid of parentheses

-2A^2-10A=0

a = -2; b = -10; c = 0;
Δ = b2-4ac
Δ = -102-4·(-2)·0
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-10}{2*-2}=\frac{0}{-4}
=0
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+10}{2*-2}=\frac{20}{-4}
=-5
$