5a(4a+15)2=0

Solution for 5a(4a+15)2=0 equation:

5a(4a+15)2=0

We multiply parentheses

40a^2+150a=0

a = 40; b = 150; c = 0;
Δ = b2-4ac
Δ = 1502-4·40·0
Δ = 22500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{22500}=150$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(150)-150}{2*40}=\frac{-300}{80}
=-3+3/4
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(150)+150}{2*40}=\frac{0}{80}
=0
$