PLEASE HELP ASAP

Which set of ordered pairs represents y as a function of x?

{(1, 3), (1, 5), (1, 7), (1, 9), (1, 11)}

{(2, 3), (3, 5), (3, -5), (-2, 8), (-2, -8)

{(1, 2), (2, 3), (3, 4), (3, 5)}

Which of the following is the equation that says that the product of a number and ten is equal to 20 percent of that number ? a) 10n= 2.0n b) 10+n=.20n c) n+ .20n=10 d) 10n=0.20n

Adj has a total of 1075 dance and rock songs on her system. the dance selection is 4 times the size of the rock selection. write a system of equations to represent the situation.

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. what distance from city a is the point where the truck and the car will meet?