Since you are given the value of c, you can plug that in and solve. So you have 3(5) + 17, which when you multiply 3 and 5, you get 15, and when you add 17 to that, you get 32.Therefore the value of 3c + 17, knowing that c is equal to 5, would be 32. Hope this helps. Feel free to ask me questions about my explanation, or any other questions you may have.
