X(3x+20)=180

Solution for X(3x+20)=180 equation:

X(3X+20)=180

We move all terms to the left:

X(3X+20)-(180)=0

We multiply parentheses

3X^2+20X-180=0

a = 3; b = 20; c = -180;
Δ = b2-4ac
Δ = 202-4·3·(-180)
Δ = 2560
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:

$\sqrt{\Delta}=\sqrt{2560}=\sqrt{256*10}=\sqrt{256}*\sqrt{10}=16\sqrt{10}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-16\sqrt{10}}{2*3}=\frac{-20-16\sqrt{10}}{6}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+16\sqrt{10}}{2*3}=\frac{-20+16\sqrt{10}}{6}
$