Algebra - Factoring Out

GRE Quant Problem Solving
1

Hey, I need some help with a question regarding one of the problems from the Algebra quiz. I’ve attached a snippet of the question along with my approach to solving it. I’m not sure why my approach is wrong (essentially I am just factoring out -1 to make it easy for me), as I believe my method should ideally yield the correct result.

Could you please help me understand what might be off in my solution?

Thanks!

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2

The problem is that you’ve essentially changed the problem from an expression to an equation, by adding the “=0” (which is why it looked as if the division by -1 was OK). In other words, we are not trying to find the roots or solve for x - we’re just factorising.

Taking -1 outside is indeed a good idea BTW - just don’t make it an equation.

3

Got it, thank you!