Is the following relation a function?

a: yes

b: no

When you arrive at the lake, your friend realises he hasn’t got any swimming trunks. you need to ride to a sports shop. the sports shop is 8350 metres away. how many metres is it to cycle there and back?

Before simplifying, how many terms are there in the expression 2x - 5y + 3 + x?

Li buys supplies so he can make and sell key chains. he begins to make a profit only after he sells 4 key chains. what point on the graph makes the most sense in this situation?