8 20 36 56 100 find the nth term

Consider the functions below. function 1 function 2 function 3 select the statement which is true about the functions over the interval [1, 2] a b function 3 has the highest average rate of change function 2 and function 3 have the same average rate of change. function and function 3 have the same average rate of change function 2 has the lowest average rate of change d.

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)