Question

Find the first, fourth, and tenth terms of the arithmetic sequence described by the given rule.
A(n)=-6+(n-1)(6)
A. 0, 18, 54
B. –6, 18, 54
C. 6, 18, 54
D. –6, 12, 48

Answer 1

the firs term
A(1)=-6+(1-1)(6)
A(1)=-6+(0)(6)
A(1)=-6



The fourh term
A(n)=-6+(n-1)(6)
A(4)=-6+(4-1)(6)
A(4)=-6+(3)(6)
A(4)=-6+18
A(4)=12


The tenth term
A(10)=-6+(10-1)(6)
A(10)=-6+(9)(6)
A(10)=-6+54
A(10)=48

Answer: 
D.  -6,12,48

Answer 2

replace n with 1, 4 and 10 and solve the equations:

 answers would be D. –6, 12, 48

-6+(1-1)*6 = -6

-6+(4-1)*6 = 12

-6+(10-1)*6 = 48