### Video Transcript

Given the function 𝑦 is equal to seven plus two 𝑥, what is the output of this function when the input is four?

The input of any function in this form is our 𝑥-value. The output is the corresponding 𝑦-value. We are given the linear function 𝑦 is equal to seven plus two 𝑥. If the input is four, we need to substitute 𝑥 equals four into the function.

As two 𝑥 means two multiplied by 𝑥, we are left with 𝑦 is equal to seven plus two multiplied by four. Using our order of operations, we multiply two and four first. This gives us eight. Seven plus eight is equal to 15. Therefore, 𝑦 equals 15.

When the input of the linear function 𝑦 equals seven plus two 𝑥 is four, the output is 15. To calculate any output in this function, we multiply the input by two and then add seven.