3=x^2-7x

Solution for 3=x^2-7x equation:

3=x^2-7x

We move all terms to the left:

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

We get rid of parentheses

-x^2+7x+3=0

We add all the numbers together, and all the variables

-1x^2+7x+3=0

a = -1; b = 7; c = +3;
Δ = b2-4ac
Δ = 72-4·(-1)·3
Δ = 61
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{61}}{2*-1}=\frac{-7-\sqrt{61}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+\sqrt{61}}{2*-1}=\frac{-7+\sqrt{61}}{-2}
$