Evaluating an expression with two variable

Substituting 2 in place of m, we get Value of an expression To find the value of an algebraic expression, we need to substitute the value of the variable in the algebraic expression For example: Value of m + 8 for m = 2 will be m+8 Substituting 2 in place of m, we get (2) + 8 = 10

Substituting the value 3 for x and -2 for y, we get Example 1: Find a value for the expression x + y when x = 3 and y = -2 x+y Substituting the value 3 for x and -2 for y, we get x+y = (3) + (-2) = 3 - 2 = 1 1 is the value of the expression Take out x and replace it with 3. Take out y and replace it with -2. Ans: 1

Replace c with 2 and b with 5 = 3 x (2) + 2 x ( 5) Example 2: Find a value for the expression 3c + 2b when c = 2 and b = 5 3 c + 2b = 3 x c + 2 x b Replace c with 2 and b with 5 = 3 x (2) + 2 x ( 5) = 6 + 10 = 16 16 is the value of the expression Ans: 16

Replace m with -2 and n with 7 = 4 x (-2) x (7) + 2 Example 3: Find a value for the expression 4mn + 2 when m = -2 and n = 7 4mn + 2 = 4 x m x n + 2 Replace m with -2 and n with 7 = 4 x (-2) x (7) + 2 = -8 x 7 + 5 = -56 + 5 = -51 -51 is the value of the expression Ans: 11

Try these Find the value for the expression. a) 2a - 8b when a = 3 and b =4 b) -9xy + 4 when x = 2 and y = 5