x^2-10x=27

Solution for x^2-10x=27 equation:

x^2-10x=27

We move all terms to the left:

x^2-10x-(27)=0

a = 1; b = -10; c = -27;
Δ = b2-4ac
Δ = -102-4·1·(-27)
Δ = 208
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:

$\sqrt{\Delta}=\sqrt{208}=\sqrt{16*13}=\sqrt{16}*\sqrt{13}=4\sqrt{13}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-4\sqrt{13}}{2*1}=\frac{10-4\sqrt{13}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+4\sqrt{13}}{2*1}=\frac{10+4\sqrt{13}}{2}
$