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ANDY
Lv 5
ANDY asked in Science & MathematicsMathematics · 8 years ago

A math problem of which I know the answer.?

I come from Astronomy and Space. I saw this problem in a magazine and believe I got the right answer. I'd like to know if any of you could confirm. I will not give you my answer, though, in order not to facilitate your finding the solution. Here goes : If x and y are positive integers, which of the following is equivalent to (2x)^3y - (2x)^y.

A. (2x)^2y

B. 2^y(x^3 - x^y)

C. (2x)^y( (2x)^2y - 1 )

D. (2x)^y(4x^y - 1)

E. (2x)^y( (2x)^3 -1 )

Update:

Thanks to you all. The answer in fact is C. Very good.

2 Answers

Relevance
  • Hector Israel
    Lv 4
    8 years ago
    Favourite answer

    C. Because you just need to factorize (2x)^3y - (2x)^y.

  • Anthony
    Lv 7
    8 years ago

    C

    (2x)^3y - (2x)^y = (2x)^y(2x^2y - 1)

    PS

    (2x)^3y = (2x)^y*(2x)^2y

    (2x)^3y - (2x)^y = (2x)^y*(2x)^2y - (2x)^y = (2x)^y[(2x)^2y - 1]

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