Question

Hi, so I know the answer to this problem (now that I got it wrong) but I'm not quite sure why I was wrong, help?

Answer 1

2x² + 2x + ? = x

⇒ ? = x - 2x² - 2x

⇒ ? = -2x² - x

Your answer is incorrect because 2x² - x² would mean x² is part of the answer, which is clearly incorrect.