Pls show your work! And write a proper answer! Thx

Isee the amount was $90.00 then reduced to $75.00 , what is the percent ?

Which math sentence can be used to determine if the triangle is a right triangle?

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.