Which answer is it?

For the equations below which statement is true ?

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?

Y= 4x + 3 y = - 1 4 x - 5 what is the best description for the lines represented by the equations?