Difference b/w matrix and vector

The american academy of pediatrics wants to conduct a survey of recently graduated family practitioners to assess why they did not choose pediatrics for their specialization. provide a definition of the population, suggest a sampling frame, and indicate the appropriate sampling unit.

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2

Given abc find the values of x and y. in your final answer, include all of your calculations.