Can somebody help me. Will mark brainliest.

What two criteria are needed for triangles to be similar

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

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.