-9-8x=-2x(7+4x)

Solution for -9-8x=-2x(7+4x) equation:

-9-8x=-2x(7+4x)

We move all terms to the left:

-9-8x-(-2x(7+4x))=0

We add all the numbers together, and all the variables

-8x-(-2x(4x+7))-9=0


We calculate terms in parentheses: -(-2x(4x+7)), so:

-2x(4x+7)

We multiply parentheses

-8x^2-14x

Back to the equation:

-(-8x^2-14x)


We get rid of parentheses

8x^2+14x-8x-9=0

We add all the numbers together, and all the variables

8x^2+6x-9=0

a = 8; b = 6; c = -9;
Δ = b2-4ac
Δ = 62-4·8·(-9)
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-18}{2*8}=\frac{-24}{16}
=-1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+18}{2*8}=\frac{12}{16}
=3/4
$