How do functions work? Could someone explain how to know which questions are functions or not

A function is an equation that has only one answer for y for every x. A function assigns exactly one output to each input of a speceified type. It is common to name a function either f(x) or g(x) instead of y. f(2) means that we should find the value of our function when x  equals 2.

Step-by-step explanation:

here is a step by step equation:

f(x) = x + 7

if:

x=2

then:

f(2) = 2 + 7 = 9

A function is linear if it can be defined by

f(x) = mx + b

Makes sense? Hope I helped

plus I'm in middle school learning this also.

d≈7.07in

step-by-step explanation: