Help me on number 17 please

First get all the x terms on the left, so you get:
x³-6x²+8x=0
Then I used long division of polynomials and trial and error to factorise it:
(x³-6x²+8x)÷(x-2)=(x²-4x)
So:
(x³-6x²+8x)=(x²-4x)(x-2)=x(x-4)(x-2)
Therefore, for this cubic to equal 0, x=0, 4, or 2. 
I hope this is clear enough to help! :)