Question the-ex

2.4 Equivalent Expressions - Simplifying polynomials
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The expression the fraction with numerator x to the power negative 2, end power, times y to the power one-half, and denominator x to the power one-third, end power, times y to the power negative 1, end fraction, where x is greater than 1 and y is greater than 1 , is equivalent to which of the following?

A.

The fraction with numerator the square root of y and denominator the cube root of x squared

B.

The fraction with numerator y times the square root of y and denominator the cube root of x squared

C.

The fraction with numerator y times the square root of y and denominator x times the square root of x

D.

The fraction with numerator y times the square root of y and denominator x squared times the cube root of x

The expression , where and , is equivalent to which of the following?

Hard-difficulty · SAT Math · Equivalent Expressions — Simplifying polynomials. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

Choice D is correct. For x is greater than 1 and y is greater than 1 , x to the one third power and y to the one half power are equivalent to the cube root of x and the square root of y, respectively. Also, x to the negative 2 power and y to the negative 1 power are equivalent to the fraction 1 over x squared, end fraction and 1 over y, respectively. Therefore, the given expression can be rewritten as the fraction with numerator, y times the square root of y, and denominator x squared, times the cube root of x, end fraction.

Choices A, B, and C are incorrect because these choices are not equivalent to the given expression for x is greater than 1 and y is greater than 1.

For example, for x equals 2 and y equals 2, the value of the given expression is 2 to the negative five sixths power; the values of the choices, however, are 2 to the negative one third power, 2 to the five sixths power, and 1, respectively.