HEY dues what is anwer for number 16 pls answer

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

If a || b and e || f , what if the value of y ?

What percent of 18 is 24? and plz explain thx.