Hi,
Question states***
x(x+7) + 42 = 2x(x+9)
x^2 + 7x + 42 = 2x^2 + 18x
x^2 + 11x - 42 = 0
(x+14)(x-3) = 0 (Tossing out the negative solution for unit measure)
x = 3units, the width of the original rectangle. the length is 10units
CHECKING our answer***
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