I believe it is the 4th one
Answer:
Quinzel sold 17 pairs of shoes last month.
Step-by-step explanation:
Let be "Q" the number of pairs of shoes Quinzel sold last month and "J" the number of pairs of shoes Joseph sold last month.
Set up a system of equations:

Solve for "J" from the first equation:

Applying the Substitution Method, you get:

q=10
Remove the radical by raising each side to the index of the radical
Hope this helps!
The answer is -4 because you do (5x-1)=(x-17)