-2m(2m+7)=-28-6m

Solution for -2m(2m+7)=-28-6m equation:

-2m(2m+7)=-28-6m

We move all terms to the left:

-2m(2m+7)-(-28-6m)=0

We add all the numbers together, and all the variables

-2m(2m+7)-(-6m-28)=0

We multiply parentheses

-4m^2-14m-(-6m-28)=0

We get rid of parentheses

-4m^2-14m+6m+28=0

We add all the numbers together, and all the variables

-4m^2-8m+28=0

a = -4; b = -8; c = +28;
Δ = b2-4ac
Δ = -82-4·(-4)·28
Δ = 512
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{512}=\sqrt{256*2}=\sqrt{256}*\sqrt{2}=16\sqrt{2}$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-16\sqrt{2}}{2*-4}=\frac{8-16\sqrt{2}}{-8}
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+16\sqrt{2}}{2*-4}=\frac{8+16\sqrt{2}}{-8}
$