Any problem they give you a T as a variable and + signs is a little annoying so make sure you read my work carefully. Here's the two answers first and you should see on my picture how I got them.

r(2t)=8t^2+4t

2r(t)=4t^2+4t

They are different answers. For the first one, it means do the function r but put in 2t instead of t. You will see on the second line of work that is exactly what I did replacing 2t twice for each t in the function. What makes it different is that the squared exponent outside of the first 2t means you have to square both the number 2 AND the t to get 4t^2. Then you still have to multiply that by 2 to get 8t^2.

In 2r(t) the idea is that you figure out the function r(t) and then multiply it by 2. All I did for this one is multiply both 2t^2 and 2t by 2. You end up with 4t^2+4t.

Just remember anytime you are working with a function that parentheses tells you what you are going to be putting in the variables.

I hope this was helpful. Please let me know if you need any clarification