(x)=x2-6x-7

Solution for (x)=x2-6x-7 equation:

(x)=x2-6x-7

We move all terms to the left:

(x)-(x2-6x-7)=0

We add all the numbers together, and all the variables

-(+x^2-6x-7)+x=0

We get rid of parentheses

-x^2+6x+x+7=0

We add all the numbers together, and all the variables

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

a = -1; b = 7; c = +7;
Δ = b2-4ac
Δ = 72-4·(-1)·7
Δ = 77
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-\sqrt{77}}{2*-1}=\frac{-7-\sqrt{77}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+\sqrt{77}}{2*-1}=\frac{-7+\sqrt{77}}{-2}
$