8=(x)(7x-1)

Solution for 8=(x)(7x-1) equation:

8=(x)(7x-1)

We move all terms to the left:

8-((x)(7x-1))=0


We calculate terms in parentheses: -(x(7x-1)), so:

x(7x-1)

We multiply parentheses

7x^2-1x

Back to the equation:

-(7x^2-1x)


We get rid of parentheses

-7x^2+1x+8=0

We add all the numbers together, and all the variables

-7x^2+x+8=0

a = -7; b = 1; c = +8;
Δ = b2-4ac
Δ = 12-4·(-7)·8
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-15}{2*-7}=\frac{-16}{-14}
=1+1/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+15}{2*-7}=\frac{14}{-14}
=-1
$