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

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

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

We move all terms to the left:

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

We multiply parentheses

2x^2+16x-((x-7)(x+8))=0

We multiply parentheses ..

2x^2-((+x^2+8x-7x-56))+16x=0


We calculate terms in parentheses: -((+x^2+8x-7x-56)), so:

(+x^2+8x-7x-56)

We get rid of parentheses

x^2+8x-7x-56

We add all the numbers together, and all the variables

x^2+x-56

Back to the equation:

-(x^2+x-56)


We add all the numbers together, and all the variables

2x^2+16x-(x^2+x-56)=0

We get rid of parentheses

2x^2-x^2+16x-x+56=0

We add all the numbers together, and all the variables

x^2+15x+56=0

a = 1; b = 15; c = +56;
Δ = b2-4ac
Δ = 152-4·1·56
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-1}{2*1}=\frac{-16}{2}
=-8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+1}{2*1}=\frac{-14}{2}
=-7
$