Please help me answer this

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?

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

Afair die is cast four times. calculate the probability of obtaining exactly two 6's round to the nearest tenth of a percent