A star becomes twice as bright every 10 years
-Exponential growth
-Exponential decay
-Linear
-None of the above

A

Step-by-step explanation:

"Twice" as bright can translate into the mathematical expression "times 2", where for every year, you multiply the previous year's brightness by 2.

Since this is a rate (using multiplication) and not a common difference (not using addition), it must be an exponential something, so eliminate C.

Now, since 2 > 1, that means this is an exponential growth. Remember that if the rate r is less than 1, then it's decay; if r is greater than 1, then it's growth.

The answer is thus A.