Which of the following graphs dont belong and why?

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Let hh represent the number of hummingbirds and ss represent the number of sunbirds that must pollinate the colony so it can survive until next year. 6h+4s > 746h+4s> 74 this year, 88 hummingbirds pollinated the colony. what is the least number of sunbirds that must pollinate the colony to ensure that it will survive until next year?

An expression for the average of x 2x and 3y