I am assuming the problem is asking you to find an equation repersenting the situation.
In this case, realize that 150 will be a constant, and 60 will be attached to the [tex]x[/tex] variable, since the price of the textbooks changes based on how many textbooks there are.
Thus, the equation is:
[tex]60x + 150 = y[/tex]
Our answer is 60x + 150 = y.
