45r^2-115r-60=0

Solution for 45r^2-115r-60=0 equation:

45r^2-115r-60=0

a = 45; b = -115; c = -60;
Δ = b2-4ac
Δ = -1152-4·45·(-60)
Δ = 24025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{24025}=155$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-115)-155}{2*45}=\frac{-40}{90}
=-4/9
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-115)+155}{2*45}=\frac{270}{90}
=3
$