We can simplify each expression step by step:

6x + 8x - 7x = 7x (Combine like terms)
23x - 19x + 5x = 9x (Combine like terms)
11x - 6x + 17 = 5x + 17 (Combine like terms)
5x + 2x - 47 = 7x - 47 (Combine like terms)

Therefore, the simplified expressions are:
7x
9x
5x + 17
7x - 47