12x2+10x-30x-25=0

Solution for 12x2+10x-30x-25=0 equation:

12x^2+10x-30x-25=0

We add all the numbers together, and all the variables

12x^2-20x-25=0

a = 12; b = -20; c = -25;
Δ = b2-4ac
Δ = -202-4·12·(-25)
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-40}{2*12}=\frac{-20}{24}
=-5/6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+40}{2*12}=\frac{60}{24}
=2+1/2
$