Question

Identify the function that is exponential.
y = −3x^5
y = 3x^8
y = −3(0.5)^x
y = −2x^4

Answer 1

In an exponential function the variable appears as an exponent.

Answer 2

I advise that you look up "exponential function" for examples, and then answer this question only after you've done that.

Answer 3

@mathmale Yes there is a lot more to exponential functions than I have stated. The tutorial here is a good start:
http://tutorial.math.lamar.edu/Classes/CalcI/ExpFunctions.aspx