-2m(-4m-6.4)=44.8

Solution for -2m(-4m-6.4)=44.8 equation:

-2m(-4m-6.4)=44.8

We move all terms to the left:

-2m(-4m-6.4)-(44.8)=0

We add all the numbers together, and all the variables

-2m(-4m-6.4)-44.8=0

We multiply parentheses

8m^2+12.8m-44.8=0

a = 8; b = 12.8; c = -44.8;
Δ = b2-4ac
Δ = 12.82-4·8·(-44.8)
Δ = 1597.44
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{-(12.8)-\sqrt{1597.44}}{2*8}=\frac{-12.8-\sqrt{1597.44}}{16}
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12.8)+\sqrt{1597.44}}{2*8}=\frac{-12.8+\sqrt{1597.44}}{16}
$