(3m-4)(m+30)=0

Solution for (3m-4)(m+30)=0 equation:

(3m-4)(m+30)=0

We multiply parentheses ..

(+3m^2+90m-4m-120)=0

We get rid of parentheses

3m^2+90m-4m-120=0

We add all the numbers together, and all the variables

3m^2+86m-120=0

a = 3; b = 86; c = -120;
Δ = b2-4ac
Δ = 862-4·3·(-120)
Δ = 8836
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8836}=94$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(86)-94}{2*3}=\frac{-180}{6}
=-30
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(86)+94}{2*3}=\frac{8}{6}
=1+1/3
$