Please help

Determine if the relation is a function. Explain your reasoning.
y=3×

While scuba diving, rajeev dove to a depth of 12.6 feet below the surface of the water and then descended another 8.7 feet. what expression can be used to find rajeev's new position? 12.6 – 8.7 –12.6 – 8.7 –12.6 – (–8.7) 12.6 – (–8.7)

Find the value of x. give reasons to justify your solutions! c ∈ ae

Talia took the bus from her home to the bank and then walked back to her home along the same route. the bus traveled at an average speed of 40 km/h and she walked at an average speed of 5 km/h. to determine the time, x, that it took talia to walk home, she used the equation 40(0.9 – x) = 5x. the time of trip 2 is hours. the distance of trip 1 is km.