1. The idea to solve this exercise is to evaluate the given functions in the points {1,2,3,4,5} (notice that these are the x component of the ordered pairs) and then eliminate the different possibilities.
The option a. cannot be because 1²=1, which is different from 2 (recall the ordered pair (1,2)).
The option b. cannot be because 2*3=6, which is different from 8 (recall the ordered pair (3,8))
The option c. is the answer, notice that 2¹=2, 2²=4, 2³=8, 2⁴=16 and 2⁵=32.
The option cannot be, because 1+2=3, which is different from 2 (recall the pair (1,2)).
2. The idea is the same of the above.
The option a. cannot be because 1²=1, which is different from 16 (recall the pair (1,16)).
The option b. cannot be because 2+15=17, which is different from 25 (recall the pair (2,25)).
The option c. cannot be because 2(1+3)=8, which is different from 16 (recall the pair (1,16)).
By elimination this should be the correct answer. Anyway, it is no difficult to check that (1+3)²=16, (2+3)²=25, (3+3)²=36, (4+3)²=49 and (5+3)²=64.
