(m+8)(6m+7)=0

Solution for (m+8)(6m+7)=0 equation:

(m+8)(6m+7)=0

We multiply parentheses ..

(+6m^2+7m+48m+56)=0

We get rid of parentheses

6m^2+7m+48m+56=0

We add all the numbers together, and all the variables

6m^2+55m+56=0

a = 6; b = 55; c = +56;
Δ = b2-4ac
Δ = 552-4·6·56
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{-(55)-41}{2*6}=\frac{-96}{12}
=-8
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(55)+41}{2*6}=\frac{-14}{12}
=-1+1/6
$