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The length of a rectangle is 2 cm more than three times the width. Find the dimensions of this rectangle if the area is 21 cm^2.

I know the answer is 9 & 2 1/3 but I found it by trial and error. Is there an easier way to find the answer to this question? Thanks!

  • math -

    the answer can be found by using algebra.
    L = 3W + 2
    L*W = 21
    (3W+2)*W = 21
    3w^2 + 2W -21 = 0
    (3W -7)(W +3) = 0
    W = 7/3
    Ignore the negative root

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