5r^2-19r-30=0

Solution for 5r^2-19r-30=0 equation:

5r^2-19r-30=0

a = 5; b = -19; c = -30;
Δ = b2-4ac
Δ = -192-4·5·(-30)
Δ = 961
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{961}=31$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-19)-31}{2*5}=\frac{-12}{10}
=-1+1/5
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-19)+31}{2*5}=\frac{50}{10}
=5
$