Please help me with this sum

Simplify a7/a4 a) 1/a3 b)-a/a2 c)a4/a3 d)a3

Which term best describes the association between variables a and b? no association a negative linear association a positive linear association a nonlinear association a scatterplot with an x axis labeled, variable a from zero to ten in increments of two and the y axis labeled, variable b from zero to one hundred forty in increments of twenty with fifteen points in a positive trend.

What set does not contain -3 the set of all real numbers the set of all integers the set of all whole numbers the set of all rational numbers