-5x2+65x+150=0

Solution for -5x2+65x+150=0 equation:

-5x^2+65x+150=0

a = -5; b = 65; c = +150;
Δ = b2-4ac
Δ = 652-4·(-5)·150
Δ = 7225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7225}=85$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(65)-85}{2*-5}=\frac{-150}{-10}
=+15
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(65)+85}{2*-5}=\frac{20}{-10}
=-2
$