15b(b=6)

Solution for 15b(b=6) equation:

15b(b=6)

We move all terms to the left:

15b(b-(6))=0

We multiply parentheses

15b^2-90b=0

a = 15; b = -90; c = 0;
Δ = b2-4ac
Δ = -902-4·15·0
Δ = 8100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8100}=90$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-90)-90}{2*15}=\frac{0}{30}
=0
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-90)+90}{2*15}=\frac{180}{30}
=6
$