What is the answer, solve for y?

In the figure shown below, m < 40 and ab =8. which equation could be used to find x?

Since opening night, attendance at play a has increased steadily, while attendance at play b first rose and then fell. equations modeling the daily attendance y at each play are shown below, where x is the number of days since opening night. on what day(s) was the attendance the same at both plays? what was the attendance? play a: y = 8x + 191 play b: y = -x^2 + 26x + 126

What are the excluded values? m+5/mn+3m