Question

The explicit rule for an arithmetic sequence is f(n) = 7 + 4(n − 1).what are the fourth and fortieth terms?

Answer 1

f(4) = 7+4(4-1)
f(4) = 7+4(3)
f(4) = 7+12
f(4) = 19
The forth term is 19 

f(40) = 7+4(40-1)
f(40) = 7+4(39)
f(40) = 7+156
f(40) = 163
The fortieth term is 163