-4x^2+80x-150=0

Solution for -4x^2+80x-150=0 equation:

-4x^2+80x-150=0

a = -4; b = 80; c = -150;
Δ = b2-4ac
Δ = 802-4·(-4)·(-150)
Δ = 4000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{4000}=\sqrt{400*10}=\sqrt{400}*\sqrt{10}=20\sqrt{10}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(80)-20\sqrt{10}}{2*-4}=\frac{-80-20\sqrt{10}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(80)+20\sqrt{10}}{2*-4}=\frac{-80+20\sqrt{10}}{-8}
$