# Trouble with the piecewise function - misplaced '&'

I can't understand how I did the piecewise function wrong, I think I've done it exactly like that before. How is the ampersand misplaced?

$$q = \begin{cases} 5x, & \text{ if }55\\ 2x, & \text{ if }41 \end{cases}$$
$$q = \begin{cases} 5x, & \text{ if }55\\ 2x, & \text{ if }41 \end{cases}$$