What will the sum of two linear expressions each with an x term always sometimes or never have an x term

The cost c, in dollars, for bananas depends on the weight w, in pounds, of the bananas. this situation is represented by the function rule c=0.5w (graph each function rule. tell whether the graph is continuous or discrete)

How do you solving the solution of each system using elimination?

If a || b and e || f , what if the value of y ?