8x+2x(x+10)=-80

Solution for 8x+2x(x+10)=-80 equation:

8x+2x(x+10)=-80

We move all terms to the left:

8x+2x(x+10)-(-80)=0

We add all the numbers together, and all the variables

8x+2x(x+10)+80=0

We multiply parentheses

2x^2+8x+20x+80=0

We add all the numbers together, and all the variables

2x^2+28x+80=0

a = 2; b = 28; c = +80;
Δ = b2-4ac
Δ = 282-4·2·80
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-12}{2*2}=\frac{-40}{4}
=-10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+12}{2*2}=\frac{-16}{4}
=-4
$