# Worked example: matching an input to a function's outputÂ (graph)

CCSS Math: HSF.IF.A.1, HSF.IF.A.2

## Video transcript

The graph of the function g is shown below What is the input value for which g of x is equal to negative 2? So what they do here is along the x axis these are the inputs and then the graph shows us what's the output so when x is equal to 7, G of 7 we see here is 1. If x equals 9, g of 9 here is 2. If x equals 6, g of 6 is equal to the y coordinate at this point is equal to 0. so what is the input value for which g is equal to negative 2? so this graph over here, this is y equals g of x. So g of x equaling to negative 2 means y of x is equal to negative 2 And so when does y equal negative 2? (muttering) when does equal negative 2? (talking) it looks like that happens right at this point. And that happens when you input negative 9 into g. g of negative 9 is negative 2 so this is going to be negative 9. And we're done.