SOLUTION: The length of a rectangle is 7cm less than twice the width. Find the perimeter of the rectangle if it’s area is 72cm squared

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Question 1152916: The length of a rectangle is 7cm less than twice the width. Find the perimeter of the rectangle if it’s area is 72cm squared
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Length, 2w-7
Width, w
Question asks for 2%282w-7%29%2B2%2Aw, perimeter.

Solve for w in w%282w-7%29=72.
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Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
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            MENTAL SOLUTION 


The equation is 


    w*(2w-7) = 72.


Multiply both sides by 2


    2w*(2w-7) = 144.


Find two integer numbers, whose product is 144 and the difference is 7.


In 6 seconds, you will find 


    2w = 16,  2w-7 = 9  (16*9 = 144).


So, the answer is: the width = 16/2 = 8;  the length = 2*8-7 = 9;  the perimeter = 2*(8+9) = 2*17 = 34.