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Topic: College Algebra Question
Replies: 4   Last Post: Sep 20, 2011 2:23 AM

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 mathstudent123 Posts: 2 Registered: 9/18/11
College Algebra Question
Posted: Sep 18, 2011 11:33 AM
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Hi Everyone,

Here is a problem that I have been working on. I cannot figure out where I am going wrong. I've typed out the problem and showed all work/steps on how to solve it. Can you please help me find my error and how to fix it? I would greatly appreciate it. Thank you!

Original problem: "The dimensions of a rectangle are such that its length is 9in more than its width. If the length were doubled and if the width were decreased by 4in, the area would be increased by 110in^2. What are the length and width of the rectangle?"

My work:

A+110=2(x+9)(x-4)

Multiplied the first term by 2
A+110=(2x+18)(x-4)

Using FOIL I multiplied the terms together
A+110=2x^2-8x+18x-72

Combined like terms
A+110=2x^2+10x-72

Subtract 110 from both sides
A=2x^2+10x-182

This the point in which I am stuck. The numbers that multiply together to make 182 is (2,91) (7,26) (13,14)

A=(2x-14)(x+13)

when factored together you get 2x^2+26x-14x-182
when like terms are combined 2x^2+12x-182, this is not right.

Thanks in advance for your help.

Date Subject Author
9/18/11 mathstudent123
9/19/11 Don Coppersmith
9/19/11 Sam2718
9/19/11 Sam2718
9/20/11 Peter Scales

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