(m-7)(5m-3)=0

Solution for (m-7)(5m-3)=0 equation:

(m-7)(5m-3)=0

We multiply parentheses ..

(+5m^2-3m-35m+21)=0

We get rid of parentheses

5m^2-3m-35m+21=0

We add all the numbers together, and all the variables

5m^2-38m+21=0

a = 5; b = -38; c = +21;
Δ = b2-4ac
Δ = -382-4·5·21
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-38)-32}{2*5}=\frac{6}{10}
=3/5
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-38)+32}{2*5}=\frac{70}{10}
=7
$