Which is an exponential decay function

Step-by-step explanation:

The last answer choice is the correct one.  The common ratio here is 0.7, which is between 0 and 1, an important criterion for recognizing an exponential decal function.  Every time x increases, f(x) will decrease.

step-by-step explanation:

total income = price of one ticket   *   number of tickets sold

  y                 =     4                                   x

so the equation is y=4x     with x≥0   because number of tickets sold can not be negative

thus the equation is a semi -line with an end point at

(0,0)

passing through :

x=1     y=4(1) = 4   so through (1,4)