Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » Math Topics » alt.math.undergrad.independent

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

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
mathstudent123

Posts: 2
Registered: 9/18/11
College Algebra Question
Posted: Sep 18, 2011 11:33 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

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.



Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.