The first term is -43.
Explanation:
an = a + (n - 1)d
a12 = a + 11d = 56, first equation
a21 = a + 20d = 101, second equation
Subtract the second equation from the first equation, cancelling +a and -a
11d - 20d = 56 - 101
-9d = -45
d = 5
Subtitute d into the first equation
a + 99 = 56
a = -43
a refers to the first term, hence the first term is -43.
Answer:

Step-by-step explanation:

Here we can solve this in 2 ways ,
Method 1 :

Here the bases are equal. So,

Method 2 :

Here the exponents are same. So,

From the last time i did it, i believe its B