The circled one is what I need help with, thank you :)

How to find the exponential function y=ca^x, with points (1,2) and (2,1)

Which of the following circles have their centers in the third quadrant? check all that apply.

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236