A characteristics of an exponential decay function is it has a constant term that is lesser than 1, this is because when you raise it a number that is lesser than 1 to higher values the result will be lesser and lesser, that is why it is called decay function. so the decay functions are a. f(x)=0.9^x and d. <span>j(x)=(4/5)^x</span>
Answer:

Step-by-step explanation:
To find the function, compare the y values. Notice that each y value decreases by being divided by 4. This means the base of the exponential is 1/4.
To find the initial value, consider the point (0,0.5). When 1/4 is raised to the 0 power, the value is 1. This leaves that the initial value is 1/2 since 1/2*1 = 0.5.
The function is
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There is no photo of the equation I can’t help you if you don’t give me something to work with