12x^2=-15x

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

12x^2=-15x

We move all terms to the left:

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

We get rid of parentheses

12x^2+15x=0

a = 12; b = 15; c = 0;
Δ = b2-4ac
Δ = 152-4·12·0
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-15}{2*12}=\frac{-30}{24}
=-1+1/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+15}{2*12}=\frac{0}{24}
=0
$