x^2-90x+1350=0

Solution for x^2-90x+1350=0 equation:

x^2-90x+1350=0

a = 1; b = -90; c = +1350;
Δ = b2-4ac
Δ = -902-4·1·1350
Δ = 2700
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:

$\sqrt{\Delta}=\sqrt{2700}=\sqrt{900*3}=\sqrt{900}*\sqrt{3}=30\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-90)-30\sqrt{3}}{2*1}=\frac{90-30\sqrt{3}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-90)+30\sqrt{3}}{2*1}=\frac{90+30\sqrt{3}}{2}
$