9x(x-4)=2x(x-4)

Solution for 9x(x-4)=2x(x-4) equation:

9x(x-4)=2x(x-4)

We move all terms to the left:

9x(x-4)-(2x(x-4))=0

We multiply parentheses

9x^2-36x-(2x(x-4))=0


We calculate terms in parentheses: -(2x(x-4)), so:

2x(x-4)

We multiply parentheses

2x^2-8x

Back to the equation:

-(2x^2-8x)


We get rid of parentheses

9x^2-2x^2-36x+8x=0

We add all the numbers together, and all the variables

7x^2-28x=0

a = 7; b = -28; c = 0;
Δ = b2-4ac
Δ = -282-4·7·0
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-28)-28}{2*7}=\frac{0}{14}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-28)+28}{2*7}=\frac{56}{14}
=4
$