-28-4x=-(8x+4)x

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

-28-4x=-(8x+4)x

We move all terms to the left:

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


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

-(8x+4)x

We multiply parentheses

-8x^2-4x

Back to the equation:

-(-8x^2-4x)


We get rid of parentheses

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

We add all the numbers together, and all the variables

8x^2-28=0

a = 8; b = 0; c = -28;
Δ = b2-4ac
Δ = 02-4·8·(-28)
Δ = 896
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:

$\sqrt{\Delta}=\sqrt{896}=\sqrt{64*14}=\sqrt{64}*\sqrt{14}=8\sqrt{14}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-8\sqrt{14}}{2*8}=\frac{0-8\sqrt{14}}{16}
=-\frac{8\sqrt{14}}{16}
=-\frac{\sqrt{14}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+8\sqrt{14}}{2*8}=\frac{0+8\sqrt{14}}{16}
=\frac{8\sqrt{14}}{16}
=\frac{\sqrt{14}}{2}
$