i. First simplify the following expressions, then determine the value of the expression by substituting a = 7.

Question

a. 13a+2a—5a b. 3a+7a
c. 17 +5a+3a d. 6a—a+2

Answer 1

a. 13a + 2a - 5a

Combine like terms:
= (13 + 2 - 5)a
= 10a

Substitute a = 7:
= 10(7)
= 70

b. 3a + 7a

Combine like terms:
= 10a

Substitute a = 7:
= 10(7)
= 70

c. 17 + 5a + 3a

Combine like terms:
= 17 + 8a

Substitute a = 7:
= 17 + 8(7)
= 17 + 56
= 73

d. 6a - a + 2

Combine like terms:
= 5a + 2

Substitute a = 7:
= 5(7) + 2
= 35 + 2
= 37