Transcript MJ2A - Davidsen Middle School

MJ2A
Ch 4.5 Simplifying Algebraic
Fractions
Bellwork
 Use the distributive property to write in
Factored form
1. 6y + 21
 Find the GCF
2. 42x2y & 38x4y2
Before we begin
 Please take out your notebook and get
ready to work…
 In today’s lesson we will look at simplifying
algebraic fractions…
 What we have learned about the GCF in
the previous lesson will help make this
easy…
 Let’s start with something we can all relate
to…
Objective 4.5
 Students will simplify algebraic fractions.
Simplifying Fractions
 Everyone has their own method for simplifying




fractions…
If you know your multiplication tables by rote
memory…you will make your life easy here…
Essentially, the goal is to get the fraction in
simplest form…that means that the GCF of the
numerator and denominator is 1…
To do that we can break down all composite
numbers to their prime components…
Let’s look at an example…
Example
 Simplify 15
60
15 =
60
3∙5
2∙2∙3∙5
 At this point you can cancel out the same numbers in the
numerator and the denominator. For example you can
cancel out the 3 and the 5.
What you are left with is:
1
1
15 =
3∙5
1∙1
1
=
=
60
2∙2 ∙3∙5
2∙2
4
1
1
Your Turn
 In the notes section of your notebook
write and simplify the following using the
cancelling out method
1. 9
12
2. 25
40
Simplifying Algebraic Fractions
 You can also use the cancelling out
strategy to simplify algebraic fractions
 Let’s look at an example…
Example
21x2y
35xy
 Write the fraction as the product of it’s prime
factors
1
1
1
2
21x y
7∙3∙x∙x∙y
=
1
35xy
7 ∙ 5 1∙ x ∙ y 1
 Cancel out common factors in the numerator
and denominator and what you are left with is
the algebraic fraction in simplest form…in this
case 3x
5
Simplify
Your Turn

In the notes section of your notebook write the
algebraic fractions and use the cancelling out
method to simplify
1. X
x3
2. 8a2
16a
3. 24
5k
Summary
 In the notes section of your notebook
summarize the key concepts covered in
today’s lesson.
 Today we discussed
 Simplifying fractions – what is the goal?
 Simplifying algebraic fractions – what method
is used to accomplish the task?
Assignment
 Practice Skills workbook lesson 4.5
Reminder:
 This assignment is due tomorrow
 I do not accept late assignments
 Use the cancelling out method to get your
answer
 Don’t forget to show your work…