Practice problems of Rational Equations ?

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Discussion Overview

The discussion revolves around finding practice problems related to rational equations and understanding how to determine the least common denominator (LCD) when dealing with algebraic denominators. Participants explore methods for factoring and identifying common factors in rational expressions.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant requests resources for practice problems on rational equations.
  • Another participant provides a link to a search for rational equations worksheets.
  • Several participants express uncertainty about how to find the least common multiple (LCM) of algebraic denominators, questioning whether they can simply multiply the terms.
  • A participant explains that the LCD is the least number that is a multiple of all denominators and suggests that multiplication is valid unless there are common factors.
  • Another participant seeks clarification on how to check for common factors in algebraic terms, proposing that factoring the denominators can help identify common factors.
  • One participant confirms understanding of the method for finding the LCM by factoring denominators and considering common factors.
  • Another participant shares an example of manipulating a rational equation to illustrate the process of finding the LCD.
  • A participant references a book that discusses the LCD and emphasizes that it is not always the product of the denominators, highlighting the importance of factoring.
  • One participant summarizes the approach to calculating the LCM for rational functions in a step-by-step manner.

Areas of Agreement / Disagreement

Participants generally agree on the importance of factoring to find the LCD, but there is no consensus on the best method for determining common factors or the specific steps to take when dealing with algebraic denominators.

Contextual Notes

Some participants express uncertainty about the definitions and methods for finding the LCD, indicating a need for clarity on factoring techniques and the treatment of common factors in algebraic expressions.

kupid
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Does anyone know where i can find some practice problems of Rational Equations ?
 
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I don't know how to take the LCM of the denominators when the denominators are algebraic terms .

For example ,

View attachment 6704

How do i take the LCM there ? Do we simply multiply the terms in the denominator ?
 

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kupid said:
I don't know how to take the LCM of the denominators when the denominators are algebraic terms .

For example ,
How do i take the LCM there ? Do we simply multiply the terms in the denominator ?

Hi kupid,

The least common denominator (LCD) of a set of fractions is the least number that is a multiple of all the denominators.
In this case that means indeed that we simply multiply the denominators.
That only changes if the denominators have a factor in common.
 
Thanks

But i don't know how to check for common factors when the denominators are algebraic terms .

How do we check for common factors when the denominators are algebraic terms ?
 
kupid said:
Thanks

But i don't know how to check for common factors when the denominators are algebraic terms .

How do we check for common factors when the denominators are algebraic terms ?

By factoring denominators to the form (x-a)(x-b)(x-c).
If both denominators contain (x-a), then the LCD has (x-a) only once.
 
Oh , That is how you find the LCM in such cases ? Thanks a lot :-)
 
using the example you posted earlier ...

$\dfrac{4}{x+2} + 3 = \dfrac{3x}{x-3}$

$\dfrac{4\color{red}{(x-3)}}{(x+2)\color{red}{(x-3)}} + \dfrac{3\color{red}{(x+2)(x-3)}}{\color{red}{(x+2)(x-3)}}= \dfrac{3x\color{red}{(x+2)}}{(x-3)\color{red}{(x+2)}}$

$4(x-3) + 3(x+2)(x-3) = 3x(x+2)$ ; $x \ne \{-2,3\}$
 
  • #10
bottom line (no pun intended) ... just make all the denominators the same using the least number of common factors possible
 
  • #11
Thanks ,To calculate an LCM for a rational function, follow these steps:
1. Factor all denominator polynomials completely.
2. Make a list that contains one copy of each factor, all multiplied together.
3. The power of each factor in that list should be the highest power that factor is
raised to in any denominator.
4. The list of factors and powers you generated is the LCM.
 

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