Remember that in a linear function of the form [tex]y=mx+b[/tex], the slope, [tex]m[/tex], is the coefficient of the independent variable [tex]x[/tex].
In our cost function [tex]c=9.90n+1060[/tex], [tex]y=c[/tex] and [tex]x=n[/tex], so we can infer that the independent variable is [tex]n[/tex]. Since the coefficient of [tex]n[/tex] is 9.90, the slope of the cost function is 9.90.
We can conclude that the slope of Kara's new store cost function is $9.90
