(m+12)(3m-5)=0

Solution for (m+12)(3m-5)=0 equation:

(m+12)(3m-5)=0

We multiply parentheses ..

(+3m^2-5m+36m-60)=0

We get rid of parentheses

3m^2-5m+36m-60=0

We add all the numbers together, and all the variables

3m^2+31m-60=0

a = 3; b = 31; c = -60;
Δ = b2-4ac
Δ = 312-4·3·(-60)
Δ = 1681
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1681}=41$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(31)-41}{2*3}=\frac{-72}{6}
=-12
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(31)+41}{2*3}=\frac{10}{6}
=1+2/3
$