What is the area of this trapezoid?

Does the problem involve permutations or? combinations? do not solve. the matching section of an exam has 4 questions and 7 possible answers. in how many different ways can a student answer the 4 ? questions, if none of the answer choices can be? repeated?

Which ordered pair (c,d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

The mass of a marine organism, in pounds, p years after it is born is given by the polynomial function r(p) = -4p2 + 300p. find the mass when p = 20 years.