(2x-18)(x+3)=0

Solution for (2x-18)(x+3)=0 equation:

(2x-18)(x+3)=0

We multiply parentheses ..

(+2x^2+6x-18x-54)=0

We get rid of parentheses

2x^2+6x-18x-54=0

We add all the numbers together, and all the variables

2x^2-12x-54=0

a = 2; b = -12; c = -54;
Δ = b2-4ac
Δ = -122-4·2·(-54)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-24}{2*2}=\frac{-12}{4}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+24}{2*2}=\frac{36}{4}
=9
$