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

Solution for 0=-2(x+1)(x+7) equation:

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

We move all terms to the left:

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

We add all the numbers together, and all the variables

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

We multiply parentheses ..

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


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

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

We multiply parentheses

-2x^2-14x-2x-14

We add all the numbers together, and all the variables

-2x^2-16x-14

Back to the equation:

-(-2x^2-16x-14)


We get rid of parentheses

2x^2+16x+14=0

a = 2; b = 16; c = +14;
Δ = b2-4ac
Δ = 162-4·2·14
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-12}{2*2}=\frac{-28}{4}
=-7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+12}{2*2}=\frac{-4}{4}
=-1
$