Question

The length of a rectangle is 8 cm greater than its width. Find the dimensions of the rectangle is its area is 105 cm^2. Write an equations and solve by factoring.

Answer 1

width = W
length = L = W+8
Area = W . L = W . (W+8) = 105
W^2 + 8W = 105
W^2 + 8W - 105 = 0
W^2 + 8W - 105 = (W+15) . (W-7) = 0
-> (W+15) = 0 or (W-7) = 0
-> W = -15 or W = 7
-15 is no a metric value, because it is negative
So the width is 7cm
W = 7cm
L = 7+8 = 15cm

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