4m(3m-45)=0

Solution for 4m(3m-45)=0 equation:

4m(3m-45)=0

We multiply parentheses

12m^2-180m=0

a = 12; b = -180; c = 0;
Δ = b2-4ac
Δ = -1802-4·12·0
Δ = 32400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{32400}=180$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-180)-180}{2*12}=\frac{0}{24}
=0
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-180)+180}{2*12}=\frac{360}{24}
=15
$