(m-8)(2m+7)=0

Solution for (m-8)(2m+7)=0 equation:

(m-8)(2m+7)=0

We multiply parentheses ..

(+2m^2+7m-16m-56)=0

We get rid of parentheses

2m^2+7m-16m-56=0

We add all the numbers together, and all the variables

2m^2-9m-56=0

a = 2; b = -9; c = -56;
Δ = b2-4ac
Δ = -92-4·2·(-56)
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-23}{2*2}=\frac{-14}{4}
=-3+1/2
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+23}{2*2}=\frac{32}{4}
=8
$