x^2-56x+672=0

Solution for x^2-56x+672=0 equation:

x^2-56x+672=0

a = 1; b = -56; c = +672;
Δ = b2-4ac
Δ = -562-4·1·672
Δ = 448
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{448}=\sqrt{64*7}=\sqrt{64}*\sqrt{7}=8\sqrt{7}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-56)-8\sqrt{7}}{2*1}=\frac{56-8\sqrt{7}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-56)+8\sqrt{7}}{2*1}=\frac{56+8\sqrt{7}}{2}
$