How to solve a stated problem  TOPIC_SOLVED

Simplificatation, evaluation, linear equations, linear graphs, linear inequalities, basic word problems, etc.

How to solve a stated problem

Postby Motherof8 on Thu Apr 07, 2011 7:08 pm

THe area of a rectangle is 144 ft. It is 7 feet longer than it is wide. What is the width of the rectangle?

I know that the area of a rectangle = length x width. I said the width was x and the length was x + 7. I wrote this equation: x(x + 7) = 144. x squared + 7x - 144 = 0. How do you work this quadratic equation out?

I can't think of any number that one could multiply to get 144 that when subtracted, = 7. 12 x 12 =144 and 6 x 24 = 144, but neither numbers when added or subtracted = 7.
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Re: How to solve a stated problem  TOPIC_SOLVED

Postby Luke53 on Thu Apr 07, 2011 7:41 pm

x^2+7x-144=0
x=9 or x=-16
x=9, since a rectangle has no negative lenght.
9*16=144
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