i. First simplify the following expressions, then determine the value of the expression by substituting a = 7.
a. 13a+2a—5a b. 3a+7a
b. 3a+ 7a
c. 17 +5a+3a d. 6a—a+2
d. 6a-a+2
a. 13a+2a-5a
Combine like terms:
13a + 2a - 5a = 15a - 5a
Simplify further:
15a - 5a = 10a
Substitute a = 7:
10(7) = 70
b. 3a + 7a
Combine like terms:
3a + 7a = 10a
Substitute a = 7:
10(7) = 70
c. 17 + 5a + 3a
Combine like terms:
5a + 3a = 8a
Add the constants:
17 + 8a
Substitute a = 7:
17 + 8(7) = 17 + 56 = 73
d. 6a - a + 2
Combine like terms:
6a - a = 5a
Add the constants:
5a + 2
Substitute a = 7:
5(7) + 2 = 35 + 2 = 37
a. To simplify the expression 13a + 2a - 5a, combine like terms:
13a + 2a - 5a = (13 + 2 - 5)a = 10a
Substituting a = 7, we have:
10a = 10(7) = 70
Therefore, the value of the expression 13a + 2a - 5a when a = 7 is 70.
b. To simplify the expression 3a + 7a, combine like terms:
3a + 7a = (3 + 7)a = 10a
Substituting a = 7, we have:
10a = 10(7) = 70
Therefore, the value of the expression 3a + 7a when a = 7 is 70.
c. To simplify the expression 17 + 5a + 3a, combine like terms:
17 + 5a + 3a = 17 + (5 + 3)a = 17 + 8a
Substituting a = 7, we have:
17 + 8a = 17 + 8(7) = 17 + 56 = 73
Therefore, the value of the expression 17 + 5a + 3a when a = 7 is 73.
d. To simplify the expression 6a - a + 2, combine like terms:
6a - a + 2 = (6 - 1)a + 2 = 5a + 2
Substituting a = 7, we have:
5a + 2 = 5(7) + 2 = 35 + 2 = 37
Therefore, the value of the expression 6a - a + 2 when a = 7 is 37.