58
Step-by-step explanation:
arithmetic sequence formula : an = a1 + ( n - 1 ) d
where an = nth term , a1 = first term , n = # of terms and d = common difference.
Here, we want to find the 19th term ( so n = 19 ) of an arithmetic sequence whose common difference is 3 ( so d = 3) and whose first term is 4 ( so a1 = 4)
So we have an = a1 + ( n - 1 ) d
n = 19 , a1 = 4 and d= 3
==> plug in values
a19 = 4 + ( 19 - 1 )3
==> subtract 1 from 19
a19 = 4 + (18)3
==> multiply 18 and 3
a19 = 4 + 54
==> add 4 and 54
a19 = 58