Question bank / Equivalent expressions

Math · Advanced MathMedium

For x>0x > 0 and y>0y > 0, which expression is equivalent to x−2y3x4y−1\frac{x^{-2}y^3}{x^4y^{-1}}?

A

y2x2\frac{y^2}{x^2}

B

y4x6\frac{y^4}{x^6}

C

x2y2x^2y^2

D

y4x2\frac{y^4}{x^2}

Show answer and explanation

Answer: B

Subtract exponents of like bases: x−2−4=x−6x^{-2 - 4} = x^{-6} and y3−(−1)=y4y^{3 - (-1)} = y^4. So the expression is x−6y4=y4x6x^{-6}y^4 = \frac{y^4}{x^6}.

Choice D adds the xx-exponents, −2+4=2-2 + 4 = 2, instead of subtracting them, −2−4=−6-2 - 4 = -6.

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