x^2-4x=672

Solution for x^2-4x=672 equation:

x^2-4x=672

We move all terms to the left:

x^2-4x-(672)=0

a = 1; b = -4; c = -672;
Δ = b2-4ac
Δ = -42-4·1·(-672)
Δ = 2704
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2704}=52$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-52}{2*1}=\frac{-48}{2}
=-24
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+52}{2*1}=\frac{56}{2}
=28
$