The numbers 28, x+2, 112 form a geometric progression. What is the 10th term?

Geometric series have the next term equal to the previous term times a constant

Term 2 = Term 1 x n = 28 x n

Term 3 = Term 2 x n = 28 x n^2

Term 3 is 112

28n^2 = 112

n = -2 or 2 depending on whether x is positive or negative.

The tenth term is 28 x n^9 = 14336 if x is positive or -14336 if x is negative