What is the sign of 3xy when x >0 and y <0

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?

When only separate discreet points are graphed it is called?

Arefrigeration system at your company uses temperature sensors fixed to read celsius (°c) values, but the system operators in your control room understand only the fahrenheit scale. you have been asked to make a fahrenheit (°f) label for the high temperature alarm, which is set to ring whenever the system temperature rises above –10°c. what fahrenheit value should you write on the label?