x^2-22=21x

Solution for x^2-22=21x equation:

x^2-22=21x

We move all terms to the left:

x^2-22-(21x)=0

a = 1; b = -21; c = -22;
Δ = b2-4ac
Δ = -212-4·1·(-22)
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-23}{2*1}=\frac{-2}{2}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+23}{2*1}=\frac{44}{2}
=22
$