0=x^2-7x+7

Solution for 0=x^2-7x+7 equation:

0=x^2-7x+7

We move all terms to the left:

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

We add all the numbers together, and all the variables

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

We get rid of parentheses

-x^2+7x-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 = 21
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{21}}{2*-1}=\frac{-7-\sqrt{21}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+\sqrt{21}}{2*-1}=\frac{-7+\sqrt{21}}{-2}
$