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SAI International School
                                                      CLASS - VIII

               Mathematics
               CHAPTER-2: Linear Equation in one variableLesson Notes-2




               SUBTOPIC : Setting up an Equation (word problem)


               Let’s understand what is an expression and equation.

               Expression is a mathematical phrase which combines, numbers, variables and
               operators to show the value of something. Example: 7x - 2(3x + 14)


               An equation is a mathematical statement wherein two expressions are set equal to
               each other.  Example: 7x - 5 = 19


















               We begin with a simple example.


               Example 1: Sum of two numbers is 74. One of the numbers is 10 more than the other.
               What are the numbers?

               Solution : We have a puzzle here. We do not know either of the two numbers, and we
               have to find them.  We are given two conditions.

                   (i)    One of the numbers is 10 more than the other.
                   (ii)    Their sum is 74.

                   We already know from Class VII how to proceed.
                    If the smaller number is taken to be x, the larger number is 10 more than x,
                    i.e., x + 10.
                    The other condition says that the sum of these two numbers x and x + 10 is 74.

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