2*x*x+15*x-120=0

Solution for 2*x*x+15*x-120=0 equation:

2x*x+15x-120=0

We add all the numbers together, and all the variables

15x+2x*x-120=0

Wy multiply elements

2x^2+15x-120=0

a = 2; b = 15; c = -120;
Δ = b2-4ac
Δ = 152-4·2·(-120)
Δ = 1185
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-\sqrt{1185}}{2*2}=\frac{-15-\sqrt{1185}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+\sqrt{1185}}{2*2}=\frac{-15+\sqrt{1185}}{4}
$