How many points do you need in order to name a ray?

Tina practice piano for 15 hours last month and 45 hours this month use multiplication to write a statement comparing me i was tina practice during the two months use addition to write a statement comparing the hours tina practice during the two months

Ineed with number 17 i don’t get it at alll

49xy +34y - 72z. determine the degree of the polynomial