hi jafrevelar

Welcome to the forum.

In the screen shot below I have shown my layout for this. (note: it will be beneficial to keep terms in neat columns)

(i) I re-ordered the terms to start with the highest power of x, and then in descending powers. Make sure the signs go with the terms.

(ii) Ask what must I multiply by x to get

(iii) now multiply (x + y - z) by this amount and put the results below. Line up matching terms to make the subtraction easier.

(iv) Subtract and write in the remaining terms.

(v) Ask what must I multiply by x to get

(vi) Subtract to get the remainder. This is zero so the division is complete.

Hope that helps,

Bob