Can I add #2e^(-2x)# and #2e^(-x)#?
You can’t add things with different variables.
When I’m not sure how something with variables works, I plug in some small numbers to think about how they work.
Here, instead of using
We don’t know without multiplying out the threes, so we can’t do it with x’s because we don’t know the value of them.
It cannot be added directly.
as explained below.
As the denominators are different, they can't be simply added.
We have to get LCM, which is nothing but