20m2-78m=-28

Solution for 20m2-78m=-28 equation:

20m^2-78m=-28

We move all terms to the left:

20m^2-78m-(-28)=0

We add all the numbers together, and all the variables

20m^2-78m+28=0

a = 20; b = -78; c = +28;
Δ = b2-4ac
Δ = -782-4·20·28
Δ = 3844
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3844}=62$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-78)-62}{2*20}=\frac{16}{40}
=2/5
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-78)+62}{2*20}=\frac{140}{40}
=3+1/2
$