-2x(4x+9)=-(8x+8)

Solution for -2x(4x+9)=-(8x+8) equation:

-2x(4x+9)=-(8x+8)

We move all terms to the left:

-2x(4x+9)-(-(8x+8))=0

We multiply parentheses

-8x^2-18x-(-(8x+8))=0


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

-(8x+8)

We get rid of parentheses

-8x-8

Back to the equation:

-(-8x-8)


We get rid of parentheses

-8x^2-18x+8x+8=0

We add all the numbers together, and all the variables

-8x^2-10x+8=0

a = -8; b = -10; c = +8;
Δ = b2-4ac
Δ = -102-4·(-8)·8
Δ = 356
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:

$\sqrt{\Delta}=\sqrt{356}=\sqrt{4*89}=\sqrt{4}*\sqrt{89}=2\sqrt{89}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-2\sqrt{89}}{2*-8}=\frac{10-2\sqrt{89}}{-16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+2\sqrt{89}}{2*-8}=\frac{10+2\sqrt{89}}{-16}
$