15z^2+6z=9

Solution for 15z^2+6z=9 equation:

15z^2+6z=9

We move all terms to the left:

15z^2+6z-(9)=0

a = 15; b = 6; c = -9;
Δ = b2-4ac
Δ = 62-4·15·(-9)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-24}{2*15}=\frac{-30}{30}
=-1
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+24}{2*15}=\frac{18}{30}
=3/5
$