Official Guide Explanation:
Problem Solving #74




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Solution and Metadata

Question: 74
Page: 71
Difficulty: 4 (Moderately Easy)
Category 1: Algebra > Simplifying Algebraic Expressions >
Category 2: Algebra > Exponents >

Explanation: Whenever a question has lots of -1's and exponents, odds are it's just checking to make sure you can pay close attention. The math itself isn't tricky, but the attention to detail keeps many test takers from getting it right. First, replace all the x's with -1's:

-(x4 + x3 + x2 + x)

= - ((-1)4 + (-1)3 + (-1)2 + (-1))

= - (1 + (-1) + 1 + (-1))

= - (1 - 1 + 1 - 1)= - 0 = 0, choice (C).

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