PSAT Math : How to evaluate rational expressions

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #1 : Expressions

If √(ab) = 8, and a= b, what is a?

Possible Answers:

4

16

64

10

2

Correct answer:

4

Explanation:

If we plug in a2 for b in the radical expression, we get √(a3) = 8. This can be rewritten as a3/2 = 8. Thus, loga 8 = 3/2. Plugging in the answer choices gives 4 as the correct answer. 

Example Question #2 : Expressions

Function_part1

 

Possible Answers:

–11/5

–37/15

37/15

9/5

–9/5

Correct answer:

–11/5

Explanation:

Fraction_part2

Fraction_part3

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