m(5m+7)=0

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

m(5m+7)=0

We multiply parentheses

5m^2+7m=0

a = 5; b = 7; c = 0;
Δ = b2-4ac
Δ = 72-4·5·0
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-7}{2*5}=\frac{-14}{10}
=-1+2/5
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+7}{2*5}=\frac{0}{10}
=0
$