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SAI International School
                                                        Class VIII


               Mathematics
               CH- 9 ALGEBRAIC EXPRESSIONS
               Lesson note-2
               SUBTOPICS:
               Addition and subtraction of algebraic expression


               Addition and Subtraction of Algebraic Expressions:

               When we are adding or subtracting two algebraic expressions, we can only add or
               subtract like terms.
               The sum of two or more like terms is a like term, with a numerical coefficient equal to
               the sum of the numerical coefficient of all the like terms.
               Similarly, the difference between two like terms is a like term with a numerical
               coefficient equal to the difference between the numerical coefficients of the two like
               terms.


               suppose, if we have to add 5xy + 3xy + 9zx

               Then like terms are 5xy and 3xy
               So, 8xy + 9zx

               Terms:
               Terms having the same variable are called Like Terms.
               Examples of Like Terms-

                 2x and -9x

                 24xy and 5yx
                     2
                 6x and 12x   2

               The terms having different variable are called, Unlike Terms.
               Examples of Unlike Terms-
                 2x and - 9y

                 24xy and 5pq
                     2
                 6x and 12y   2


                                                                      3
                                                                                             3
                                                                                   2
                       Add 5xy – 3x – 12y +5x, xy – 3x – 12yz +5x and y – 6x – zy +5x .
                                     2
                       Solution:
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