m(5m-5)=7

Solution for m(5m-5)=7 equation:

m(5m-5)=7

We move all terms to the left:

m(5m-5)-(7)=0

We multiply parentheses

5m^2-5m-7=0

a = 5; b = -5; c = -7;
Δ = b2-4ac
Δ = -52-4·5·(-7)
Δ = 165
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-\sqrt{165}}{2*5}=\frac{5-\sqrt{165}}{10}
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+\sqrt{165}}{2*5}=\frac{5+\sqrt{165}}{10}
$