(5m+6)(4m-7)=0

Solution for (5m+6)(4m-7)=0 equation:

(5m+6)(4m-7)=0

We multiply parentheses ..

(+20m^2-35m+24m-42)=0

We get rid of parentheses

20m^2-35m+24m-42=0

We add all the numbers together, and all the variables

20m^2-11m-42=0

a = 20; b = -11; c = -42;
Δ = b2-4ac
Δ = -112-4·20·(-42)
Δ = 3481
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3481}=59$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-11)-59}{2*20}=\frac{-48}{40}
=-1+1/5
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-11)+59}{2*20}=\frac{70}{40}
=1+3/4
$