A=3x(x-6)

Solution for A=3x(x-6) equation:

=3A(A-6)

We move all terms to the left:

-(3A(A-6))=0


We calculate terms in parentheses: -(3A(A-6)), so:

3A(A-6)

We multiply parentheses

3A^2-18A

Back to the equation:

-(3A^2-18A)


We get rid of parentheses

-3A^2+18A=0

a = -3; b = 18; c = 0;
Δ = b2-4ac
Δ = 182-4·(-3)·0
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-18}{2*-3}=\frac{-36}{-6}
=+6
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+18}{2*-3}=\frac{0}{-6}
=0
$