3m^2-21m-90=0

Solution for 3m^2-21m-90=0 equation:

3m^2-21m-90=0

a = 3; b = -21; c = -90;
Δ = b2-4ac
Δ = -212-4·3·(-90)
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-39}{2*3}=\frac{-18}{6}
=-3
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+39}{2*3}=\frac{60}{6}
=10
$