Answer:
A) -19
Step-by-step explanation:
Basics first:
An arithmetic sequence progresses with numbers being added or subtracted by a constant value.
After understanding that, as soon as we have any two values of the sequence we can find the constant value which is added or subtracted.
Look:
The 11th term is -75.
12 terms later (23th), the term is 4.
In other words, after "jumping" 12 terms, we went up 84 numbers (75 + 9)
To find the size of each "jump" we just divide the total number variation (84) by the number of jumps (12)
84/12 = 7
Now that we know the size of each jump, we can either jump 4 terms back from the 23rd term or jump 8 terms forward from the 11th term.
I will jump 4 terms back from the 23rd term:
19th term = 23rd term - 4 jumps
19th term = 9 - 4 * 7 //Remember that 7 is the jump size
19th term = 9 - 28
19th term = -19
