-4x^2-4x=(x-5)(-5x-3)

Solution for -4x^2-4x=(x-5)(-5x-3) equation:

-4x^2-4x=(x-5)(-5x-3)

We move all terms to the left:

-4x^2-4x-((x-5)(-5x-3))=0

We multiply parentheses ..

-4x^2-((-5x^2-3x+25x+15))-4x=0


We calculate terms in parentheses: -((-5x^2-3x+25x+15)), so:

(-5x^2-3x+25x+15)

We get rid of parentheses

-5x^2-3x+25x+15

We add all the numbers together, and all the variables

-5x^2+22x+15

Back to the equation:

-(-5x^2+22x+15)


We get rid of parentheses

-4x^2+5x^2-22x-4x-15=0

We add all the numbers together, and all the variables

x^2-26x-15=0

a = 1; b = -26; c = -15;
Δ = b2-4ac
Δ = -262-4·1·(-15)
Δ = 736
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{736}=\sqrt{16*46}=\sqrt{16}*\sqrt{46}=4\sqrt{46}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-26)-4\sqrt{46}}{2*1}=\frac{26-4\sqrt{46}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-26)+4\sqrt{46}}{2*1}=\frac{26+4\sqrt{46}}{2}
$