30=x(3x-20)

Solution for 30=x(3x-20) equation:

30=x(3x-20)

We move all terms to the left:

30-(x(3x-20))=0


We calculate terms in parentheses: -(x(3x-20)), so:

x(3x-20)

We multiply parentheses

3x^2-20x

Back to the equation:

-(3x^2-20x)


We get rid of parentheses

-3x^2+20x+30=0

a = -3; b = 20; c = +30;
Δ = b2-4ac
Δ = 202-4·(-3)·30
Δ = 760
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{760}=\sqrt{4*190}=\sqrt{4}*\sqrt{190}=2\sqrt{190}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-2\sqrt{190}}{2*-3}=\frac{-20-2\sqrt{190}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+2\sqrt{190}}{2*-3}=\frac{-20+2\sqrt{190}}{-6}
$