Exponential functions:

One-to-One Functions:
If different inputs have different outputs, and vice versa AKA one x-value doesn’t have multiple y-values
Horizontal-Line Test:
If a horizontal line touches the function more than once, then it is NOT a One-to-One Function

Doubling Time and Half-Life:

How to write an exponential function, with two points given:

OR

And then substitute the a, x and y-values in and solve for b
Things to remember:
Always Round-UP when dealing with years
Ex. 2005.2 is 2006 obviously
Exponential equations that are a little tricky:

Find the rate or time in a compound interest equation:

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