-4(-x-2)x+5=31

Solution for -4(-x-2)x+5=31 equation:

-4(-x-2)x+5=31

We move all terms to the left:

-4(-x-2)x+5-(31)=0

We add all the numbers together, and all the variables

-4(-1x-2)x+5-31=0

We add all the numbers together, and all the variables

-4(-1x-2)x-26=0

We multiply parentheses

4x^2+8x-26=0

a = 4; b = 8; c = -26;
Δ = b2-4ac
Δ = 82-4·4·(-26)
Δ = 480
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:

$\sqrt{\Delta}=\sqrt{480}=\sqrt{16*30}=\sqrt{16}*\sqrt{30}=4\sqrt{30}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-4\sqrt{30}}{2*4}=\frac{-8-4\sqrt{30}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+4\sqrt{30}}{2*4}=\frac{-8+4\sqrt{30}}{8}
$