This problem is an example of an arithmetic series.
The common difference of the second term (15) with the first term (9) and the third term (21) with the second term (15) [15-9=6; 21-15=6] is 6.
The formula for solving this is:
An= A1 +(n-1)*d where An is the nth term, A1 is the first term, n is the number of terms and d is the common difference.
An=9+ (31-1)*6 = 189
The answer is 189.
C
Mathy49 See you later lol deleted my old one cuz it's in spanish
The answer is
<span>A. 2/14, 3/21, 4/28
B. 1/8, 2/16, 3/24
C. 1/9, 2/18, 3/27
D. 5/40, 5/45, 5/50</span>
Answer:
k=-11
Step-by-step explanation:

if
is a factor,


the equation is the horizontal line which parts through (-5,6), since it has no slope.