How do I simplify this algebraic expression with a brain fart?

[cotufa]

I can't seem to see how this simplifies, having an algebra brain fart

$$2(2-x)^2-x(2-x)^2- 2/3 (2-x)^3$$

$$(2-x)(2-x)^2- 2/3 (2-x)^3$$

$$1/3(2-x)^3$$

 

[approx]

Let's replace (2-x) with A.
Then we have 2A^2 - xA^2 - (2/3)A^3
Then we get (2-x) A^2 - (2/3)A^3
since A=2-x, this gives
(A^3) - (2/3)A^3 = (1/3)A^3 ===> now just replace A with 2-x

approx

 

[cotufa]

Thank you