This is an angle whose measure is exactly 90°

Me figure out the process to determine x you appreciate it : )

Find the average rate of change for f(x) = x2 − 3x − 10 from x = −5 to x = 10.

Due to bad planning, two of the local schools have their annual plays on the same weekend. while 457 people attend one, and 372 attend the other, only 104 people were able to attend both. how many people went to at least one play?