Hello from MrBillDoesMath!
Answer:
Zero ( or no) solutions
Discussion:
Suppose that 9x -16 = 9x - 23 as stated in the question. Subtracting 9x from both sides gives
(9x - 9x) - 16 = (9x - 9x) - 23 or
-16 = -23
As -16 does not equal -23 the equation has no (or zero) solutions
Thank you,
MrB