Operations with Negative #

GRE Quant Problem Solving
1

Hi! For the PrepSwift Operations with Negative numbers question #6: “x equals the sum of a negative number with an even exponent and a negative number with an odd exponent” -

How do I know if this question is referencing ex: (-5)^2 or -5^2 based on the wording alone?

2

It’s the first one, I think

3

x = p^a + q^b where p < 0, a is even, q < 0 and b is odd.

4

Do you think it would be outlined on the exam or can it be phrased similarly? How will I know if it’s referencing () or not?

5

I don’t think so, you gotta check for brackets and deduce it yourself

6

We need to know the answer to the question of whether to assume parenthesis or not as that will decide the answer to this question.

7

You do have to assume brackets here.

8

Ok. Then it is not a good question. Assumption can work work both ways

9

There is no “assumption” going here - the issues I am seeing here are simply due to students not understanding what the problem is, and in particular not spotting the difference in wording between (-x)^k and -(x^k).

In other words, the question remains perfectly valid.

10

Thanks - can you explain the difference in wording please? I can’t tell from the wording of the question whether we it is referring to (−x)k and −(xk).

11

Let x > 0.

  • negative number = -x
  • negative number with even exponent = (-x)^k (where k is even)
  • positive number: x
  • positive number with even exponent = x^k
  • negative of a positive number with even exponent: -(x^k)

Do you see the difference?

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