In this function machine, we put 𝑥 in and get 𝑦 out. Which of these equations describes the rule? 𝑦 equals 𝑥 plus five, 𝑦 equals 𝑥 plus eight, 𝑦 equals 𝑥 times five, 𝑦 equals 𝑥 times eight, or 𝑦 equals 𝑥 minus five.
This function table has given us a very important clue. In this function machine or in this function table, you multiply 𝑥 by five and that gives you 𝑦. For example, if we have an 𝑥-value of two, we multiply two times five and that gives us our 𝑦-value of 10.
We are looking for an equation that says 𝑦 equals 𝑥 times five. Only one of the answer choices — only one of the equations — describes the rule correctly 𝑦 equals 𝑥 times five.