p^2-30p+189=0

Solution for p^2-30p+189=0 equation:

p^2-30p+189=0

a = 1; b = -30; c = +189;
Δ = b2-4ac
Δ = -302-4·1·189
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$p_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$p_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$p_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-12}{2*1}=\frac{18}{2}
=9
$
$p_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+12}{2*1}=\frac{42}{2}
=21
$