The arithmetic sequence is going up in 4’s (1 x 4 = 4, 4 x 4 = 16) Therefore the answer is just 4n
2) 0.5n (1/2n) The arithmetic sequence is going up in 0.5’s (1 x 0.5 = 1/2, 1/2 x 0.5 = 1/4) Therefore the answer is just 0.5n or if you need it in a fraction it is (1/2n)
3) -7n The arithmetic sequence is going up in -7’s (7 x -7 = -14, -14 x -7 = 28) Therefore the answer is just -7n