Enter the value of n so that th expression (9y - 8) + (y+ 5) is equal to (ny - 3)

Country carpets charges $22 per square yard for carpeting, and an additional installation fee of $100. city carpets charges $25 per square yard for the same carpeting, and an additional installation fee of $70

How do you determine whether a relationship represented as as graph is linear or nonlinear

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a