Evaluate 1/3m -1-1/2n when m=21 and n=12

What is the area of the trapezoid shown ?

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?

Is the number 128.439 a rational number