(p+10)(p-15)=0

Solution for (p+10)(p-15)=0 equation:

(p+10)(p-15)=0

We multiply parentheses ..

(+p^2-15p+10p-150)=0

We get rid of parentheses

p^2-15p+10p-150=0

We add all the numbers together, and all the variables

p^2-5p-150=0

a = 1; b = -5; c = -150;
Δ = b2-4ac
Δ = -52-4·1·(-150)
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$p_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$p_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$p_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-25}{2*1}=\frac{-20}{2}
=-10
$
$p_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+25}{2*1}=\frac{30}{2}
=15
$