Work out 5 3/4 - 2 1/4

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.

Which expression can be used to determine the slope of the line that passes through the points -6, three and one, -9

Which one ? is the answer and how to find this answer