A function has the rule “double the input, then subtract 4.”

Question

Using x to represent the input, complete the diagram with an expression for this rule. What expression represents “double the input, then subtract 4?”
x
Input Output Arrow
Input Output Arrow
y

Answer 1

To express the rule “double the input, then subtract 4,” we can break it down step by step:

1. Double the input (x): This means we multiply the input \(x\) by 2, which gives us \(2x\).

2. Subtract 4: After doubling the input, we subtract 4 from the result obtained in step 1, leading to the expression \(2x - 4\).

Thus, the complete expression for the rule "double the input, then subtract 4" is:

\[ y = 2x - 4 \]

In the diagram you mentioned, it would look like this:

   x
   |
   v
   2x - 4
   |
   v
   y

So, the final expression that you can use in the diagram for y is \(y = 2x - 4\).