-10x^2-25x+15=0

Solution for -10x^2-25x+15=0 equation:

-10x^2-25x+15=0

a = -10; b = -25; c = +15;
Δ = b2-4ac
Δ = -252-4·(-10)·15
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-35}{2*-10}=\frac{-10}{-20}
=1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+35}{2*-10}=\frac{60}{-20}
=-3
$