Answer:
12, 21, 39
Step-by-step explanation:
Arithmetic sequence described by this rule in the question is :
A(n) = 12 + (n-1)(3)
a. Finding the first term
n = 1
A(n) = 12 + (n-1)(3)
A(1) = 12 + ( 1 - 1)(3)
A(1) = 12 + (0)(3)
A(1) = 12 + 0
A(1) = 12
Therefore the first term = 12.
b. Finding the fourth term
n = 4
A(n) = 12 + (n-1)(3)
A(4) = 12 + ( 4 - 1)(3)
A(4) = 12 + (3)(3)
A(4) = 12 + 9
A(4) = 21
Therefore the fourth term = 21
c. Finding the tenth term
n = 10
A(n) = 12 + (n-1)(3)
A(10) = 12 + ( 10- 1)(3)
A(10) = 12 + (9)(3)
A(10) = 12 + 27
A(10) = 39
Therefore the tenth term = 39
The first term = 12, the fourth term = 21 and the tenth term = 39
