function (`x`)

`f  (x)` = function (`x`)

`f` = machine

`x` = input

1. `f  (x) = 2x^2`

This machine "`f`" takes the input `x`, squares it, then multiplies it by 2.

2. `f  (x) = 2x^2 - 3x - 5`

This machine "`f`" takes the input `x` and squares it and multiplies it by 2, it then multiplies the input `x` by 3 and takes it away, it then takes away 5.

3. `f  (-2)` when `f  (x) = 2x^2 - 3x - 5`

This machine "`f`", takes the input (-2) and squares it and multiplies it by 2, it then multiplies the input (-2) by 3 and takes it away, it then takes away 5.