1.25x^2-60x-900=0

Solution for 1.25x^2-60x-900=0 equation:

1.25x^2-60x-900=0

a = 1.25; b = -60; c = -900;
Δ = b2-4ac
Δ = -602-4·1.25·(-900)
Δ = 8100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8100}=90$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-60)-90}{2*1.25}=\frac{-30}{2.5}
=-12
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-60)+90}{2*1.25}=\frac{150}{2.5}
=60
$