# EVALUATE ALGEBRAIC EXPRESSIONS

To evaluate an algebraic expression means to find the value of the expression when the variable is replaced by a given number.

To evaluate an expression, we substitute the given number for the variable in the expression and then simplify the expression using the order of operations.

Evaluate the algebraic expression for the given values.

Example 1 :

7x + 8 when x = 2

Solution :

Apply x = 2 in the function, we get

= 7(2) + 8

= 14 + 8

= 22

Example 2 :

5x − 4 when x = 6

Solution :

Apply x = 6 in the function, we get

= 5(6) - 4

= 30 - 4

= 26

Example 3 :

x2 when x = 12

Solution :

Apply x = 12 in the function, we get

= 122

= 144

Example 4 :

4x when x = 2

Solution :

Apply x = 2 in the function, we get

= 42

= 16

Example 5 :

x2 + 3x - 7 when x = 4

Solution :

Apply x = 2 in the function, we get

= 22 + 3(2) - 7

= 4 + 6 - 7

= 10 - 7

= 3

Example 6 :

(x - y)when x = 10 and y = 7

Solution :

Apply x = 10 and y = 7 in the function, we get

= (x - y)2

= (10 - 7)2

= 32

= 9

Example 7 :

a2 + bwhen a = 3 and b = 8

Solution :

Apply a = 3 and b = 8 in the function, we get

= a2 + b2

= 32 + 82

= 9 + 64

= 73

Example 8 :

r- swhen r = 12 and s = 5

Solution :

Apply r = 12 and s = 5 in the function, we get

= r- s2

= 122 - 52

= 144 - 25

= 119

Example 9 :

2L + 2W when L = 15 and W = 12

Solution :

Apply L = 15 and W = 12 in the function, we get

= 2(15) + 2(12)

= 30 + 24

= 54

Example 10 :

2x + 4y - 5 when x = 7 and y = 8

Solution :

Apply x = 7 and y = 8 in the function, we get

= 2(7) + 4(8) - 5

= 14 + 32 - 5

= 46 - 5

= 41

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