Thank you for the detailed reply, can I ask you on step 3 of your workings where the 1 comes from, I can't understand it, sorryRobegk, I got this:
(x−y)2 + 3(y−x)3 =
(x−y)2 − 3(x−y)3 =
(x−y)2[1−3(x−y)] =
(x−y)2(1−3x+3y) =
(x−y)2(−3x+3y+1)
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What did you get?
Hi Robegk. He factored out the expression (x-y)^2. Like this pattern:where the 1 comes from