Question which-

2.4 Equivalent Expressions - Simplifying polynomials
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Which expression is equivalent to y+12x-8+yx-8x2y-8xy?

A.

x y + y + 4 x 3 y - 16 x 2 y + 64 x y

B.

x y + 9 y + 12 x 2 y - 8 x y + x - 8

C.

x y 2 + 13 x y - 8 y x 2 y - 8 x y

D.

x y 2 + 13 x y - 8 y x 3 y - 16 x 2 y + 64 x y

Which expression is equivalent to y + 12 x - 8 + y x - 8

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 C is correct. Factoring the denominator in the second term of the given expression gives y+12x-8+yx-8xyx-8. This expression can be rewritten with common denominators by multiplying the first term by xyxy, giving xyy+12xyx-8+yx-8xyx-8. Adding these two terms yields xyy+12+yx-8xyx-8. Using the distributive property to rewrite this expression gives xy2+12xy+xy-8yx2y-8xy. Combining the like terms in the numerator of this expression gives xy2+13xy-8yx2y-8xy.

Choice A is incorrect and may result from conceptual or calculation errors.

Choice B is incorrect and may result from conceptual or calculation errors.

Choice D is incorrect and may result from conceptual or calculation errors.