Part A) It's because at the intersection point, the two graphs have the same X and Y values, thus making it a common ground(and the answer for the equations)
Part B)
-3 64 3.125
-2 16 3.25
-1 4 3.5
0 1 4
1 0.25 5
2 1/16 7
3 1/64 11
where first column is x values, second column is 4^-x and third column is 2^x + 3
Part C) either find the zero of 4 ^ -x - 2 ^ x - 3 = y or graph 4 ^ -x = y and
2 ^ x - 3 = y and find the intersection