I tried and couldn't get it can someone help me out

This problem seems badly worded and/or vague.

It looks like you plugged x = 3 into the inverse function to get 3 as the output, which is correct.

However it seems like your teacher wants you to find the (x,y) point on f(x). This means s/he is asking "what x value will get us y = 10?" As you found through working with the inverse, the x value x = 3 does that.

We can see it as such

f(x) = 3x+1

f(3) = 3*3+1

f(3) = 10

So in a sense, you were working backwards.

The point (3,10) is on the graph of f(x)

While the point (10,3) is on the graph of

It's likely your teacher wants you to select choice C

y=mx+b

step-by-step explanation:

m slope

b y-intercept