Given the exponential function a(x) = p(1 + r)x, what value for r will make the function a decay function?

ANSWER
Any value of r in between -1 and 0 (exclusive on both sides).
For example, r = -0.1 or r = -0.5

EXPLANATION
You did not specify any answer choices; all we can do is state a range of values for r.

We have exponential function 

We note that the base is "1 + r"

For an exponential function to be a decay function, the base must be between 0 and 1 exclusive.

   

Therefore, the values for r must lie in the range -1 < r < 0 (between -1 and 0 exclusive)

In interval notation, this is expressed as (-1, 0)

I'm sure the answer is a

Idon’t feel like doing the math but you need to do 2.24 divided by 7