What’s the answer to these 2

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

Is there a direction u in which the rate of change of f(x,y)equals=x squared minus 3 xy plus 4 y squaredx2−3xy+4y2 at p(1,2) equals 14? give reasons for your answer. choose the correct answer below. a. no. the given rate of change is smaller than the minimum rate of change. b. no. the given rate of change is larger than the maximum rate of change. c. yes. the given rate of change is larger than the minimum rate of change and smaller than the maximum rate of change.