3x=9x2-30

Solution for 3x=9x2-30 equation:

3x=9x^2-30

We move all terms to the left:

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

We get rid of parentheses

-9x^2+3x+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:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

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