SOLUTION: a rectangle has an area of 84 square feet. the width is x and the length is x+5. find the dimension of the rectangle.

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Question 1153785: a rectangle has an area of 84 square feet. the width is x and the length is x+5. find the dimension of the rectangle.
Found 2 solutions by josgarithmetic, math_helper:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
84=highlight%287%29%2Ahighlight%2812%29



If you want a longer way, you can try x%28x%2B5%29=84, and solve as the quadratic equation.

Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!


Method 1:

Look for factors of 84 that have a difference of 5:



84 =

4*21

6*14

7*12   <--- width is 7, length is 12





Method 2:

Solve algebraically.

+x%2A%28x%2B5%29+=+84+ 

+x%5E2+%2B+5x+-+84+=+0+

// Note that method 1 is basically the same as factoring this expression



+%28x-7%29%2A%28x%2B12%29+=+0+  -->  x = 7 (width) and x + 5 = 12 (length)