9a^2-3a=30

Solution for 9a^2-3a=30 equation:

9a^2-3a=30

We move all terms to the left:

9a^2-3a-(30)=0

a = 9; b = -3; c = -30;
Δ = b2-4ac
Δ = -32-4·9·(-30)
Δ = 1089
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1089}=33$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-33}{2*9}=\frac{-30}{18}
=-1+2/3
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+33}{2*9}=\frac{36}{18}
=2
$