(m-7)(-2m+5)=0

Solution for (m-7)(-2m+5)=0 equation:

(m-7)(-2m+5)=0

We multiply parentheses ..

(-2m^2+5m+14m-35)=0

We get rid of parentheses

-2m^2+5m+14m-35=0

We add all the numbers together, and all the variables

-2m^2+19m-35=0

a = -2; b = 19; c = -35;
Δ = b2-4ac
Δ = 192-4·(-2)·(-35)
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-9}{2*-2}=\frac{-28}{-4}
=+7
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+9}{2*-2}=\frac{-10}{-4}
=2+1/2
$