Question

The rectangle below has an area of x^2-x-72 and a length of x+8 meters.
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What expression represents the width of the rectangle?

Answer 1

area of rectangle = length x width

so width = area / length = (x^2-x-72) / (x+8); after factorizing

width = (x-9)(x+8)/(x+8)

= x - 9

Answer 2

x^2-x-72 

what timed together makes -72 and added together make -1 
1 & 72 (no)
2 & 36 (no)
3 & 24 (no)
4 & 18 (no)
6 & 12 (no)
8 & 9 < its this one . +8 x -9 = -72 but also +8-9=-1 
as we already have the length which is (x+8) the width would be (x-9)