x(X+3)-270=0

Solution for x(X+3)-270=0 equation:

x(x+3)-270=0

We multiply parentheses

x^2+3x-270=0

a = 1; b = 3; c = -270;
Δ = b2-4ac
Δ = 32-4·1·(-270)
Δ = 1089
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1089}=33$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-33}{2*1}=\frac{-36}{2}
=-18
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+33}{2*1}=\frac{30}{2}
=15
$