-6x-28=-7(8x+4)x=0

Solution for -6x-28=-7(8x+4)x=0 equation:

-6x-28=-7(8x+4)x=0

We move all terms to the left:

-6x-28-(-7(8x+4)x)=0


We calculate terms in parentheses: -(-7(8x+4)x), so:

-7(8x+4)x

We multiply parentheses

-56x^2-28x

Back to the equation:

-(-56x^2-28x)


We get rid of parentheses

56x^2+28x-6x-28=0

We add all the numbers together, and all the variables

56x^2+22x-28=0

a = 56; b = 22; c = -28;
Δ = b2-4ac
Δ = 222-4·56·(-28)
Δ = 6756
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{6756}=\sqrt{4*1689}=\sqrt{4}*\sqrt{1689}=2\sqrt{1689}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(22)-2\sqrt{1689}}{2*56}=\frac{-22-2\sqrt{1689}}{112}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(22)+2\sqrt{1689}}{2*56}=\frac{-22+2\sqrt{1689}}{112}
$