h(t) = -2t+2 , Find h (-3t)

"h" is just the name of the function.  Often f is used but any letter can be used :)

And yes, you just replace the original t with -3t like the 2nd anon did. 

h(-3t) = -2(-3t) + 2

h(-3t) = 6t + 2

h(t) = -2t+2 , Find h (-3t)

Assuming I understand you

Then your answer is:

-3 h t

I don't know why the first answer contains an 'h'.  What that is saying is that you should plug in '-3t' for each 't' you see in the problem so:  h(-3t) = -2(-3t) + 2