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

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

=(-7A+7)(-A-1)

We move all terms to the left:

-((-7A+7)(-A-1))=0

We add all the numbers together, and all the variables

-((-7A+7)(-1A-1))=0

We multiply parentheses ..

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


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

(+7A^2+7A-7A-7)

We get rid of parentheses

7A^2+7A-7A-7

We add all the numbers together, and all the variables

7A^2-7

Back to the equation:

-(7A^2-7)


We get rid of parentheses

-7A^2+7=0

a = -7; b = 0; c = +7;
Δ = b2-4ac
Δ = 02-4·(-7)·7
Δ = 196
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{196}=14$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-14}{2*-7}=\frac{-14}{-14}
=1
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+14}{2*-7}=\frac{14}{-14}
=-1
$