X^2-56x-756=0

Solution for X^2-56x-756=0 equation:

X^2-56X-756=0

a = 1; b = -56; c = -756;
Δ = b2-4ac
Δ = -562-4·1·(-756)
Δ = 6160
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:

$\sqrt{\Delta}=\sqrt{6160}=\sqrt{16*385}=\sqrt{16}*\sqrt{385}=4\sqrt{385}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-56)-4\sqrt{385}}{2*1}=\frac{56-4\sqrt{385}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-56)+4\sqrt{385}}{2*1}=\frac{56+4\sqrt{385}}{2}
$