(X+3)(x-4)(2)=120

Solution for (X+3)(x-4)(2)=120 equation:

(X+3)(X-4)(2)=120

We move all terms to the left:

(X+3)(X-4)(2)-(120)=0

We multiply parentheses ..

(+X^2-4X+3X-12)2-120=0

We multiply parentheses

2X^2-8X+6X-24-120=0

We add all the numbers together, and all the variables

2X^2-2X-144=0

a = 2; b = -2; c = -144;
Δ = b2-4ac
Δ = -22-4·2·(-144)
Δ = 1156
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1156}=34$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-34}{2*2}=\frac{-32}{4}
=-8
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+34}{2*2}=\frac{36}{4}
=9
$