Answer:
-33 or 33
Step-by-step explanation:
The seventh term of an AP is written as:
The eleventh term of an AP is written as:
If the 7th term is 11 times the 11th term, then;
Expand to get:
We must have a=-52 and d=5
Or
a=52 and d=-5
For the first case, the 18th term is :
For the second case,
