F(5)= 3.(5)+2=15+2=17
Another example: F(0)=3.(0)+2=0+2=2
You just replace the value in the two sides.
Answer:
I think x is equal to 6. Correct me if I'm wrong!
Please ask the question in English, if you are not able to, I believe you are in the wrong language section and suggest you try something else before you get your question taken down.