12b^2-15b=-9b

Solution for 12b^2-15b=-9b equation:

12b^2-15b=-9b

We move all terms to the left:

12b^2-15b-(-9b)=0

We get rid of parentheses

12b^2-15b+9b=0

We add all the numbers together, and all the variables

12b^2-6b=0

a = 12; b = -6; c = 0;
Δ = b2-4ac
Δ = -62-4·12·0
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-6}{2*12}=\frac{0}{24}
=0
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+6}{2*12}=\frac{12}{24}
=1/2
$