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

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

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

We add all the numbers together, and all the variables

(-1x+2)(3x+18)=0

We multiply parentheses ..

(-3x^2-18x+6x+36)=0

We get rid of parentheses

-3x^2-18x+6x+36=0

We add all the numbers together, and all the variables

-3x^2-12x+36=0

a = -3; b = -12; c = +36;
Δ = b2-4ac
Δ = -122-4·(-3)·36
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*-3}=\frac{-12}{-6}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+24}{2*-3}=\frac{36}{-6}
=-6
$