-2x(-2x-7)=-2(x+1)

Solution for -2x(-2x-7)=-2(x+1) equation:

-2x(-2x-7)=-2(x+1)

We move all terms to the left:

-2x(-2x-7)-(-2(x+1))=0

We multiply parentheses

4x^2+14x-(-2(x+1))=0


We calculate terms in parentheses: -(-2(x+1)), so:

-2(x+1)

We multiply parentheses

-2x-2

Back to the equation:

-(-2x-2)


We get rid of parentheses

4x^2+14x+2x+2=0

We add all the numbers together, and all the variables

4x^2+16x+2=0

a = 4; b = 16; c = +2;
Δ = b2-4ac
Δ = 162-4·4·2
Δ = 224
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:

$\sqrt{\Delta}=\sqrt{224}=\sqrt{16*14}=\sqrt{16}*\sqrt{14}=4\sqrt{14}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-4\sqrt{14}}{2*4}=\frac{-16-4\sqrt{14}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+4\sqrt{14}}{2*4}=\frac{-16+4\sqrt{14}}{8}
$