Which of the following are functions?

a) y - x = 7

b) y = 6

c) x = 2

d) x = y to the power of 2

A) D)

Step-by-step explanation:

Multiple choice? Yes or no?

If yes:

A function is an equation or an expression that involves more than one variable, for example, (b^x+t)

So, your possible answers are A) and D), since there is more than one variable involved.