2x^2+15x=-12

Solution for 2x^2+15x=-12 equation:

2x^2+15x=-12

We move all terms to the left:

2x^2+15x-(-12)=0

We add all the numbers together, and all the variables

2x^2+15x+12=0

a = 2; b = 15; c = +12;
Δ = b2-4ac
Δ = 152-4·2·12
Δ = 129
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{129}}{2*2}=\frac{-15-\sqrt{129}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+\sqrt{129}}{2*2}=\frac{-15+\sqrt{129}}{4}
$