Hey I need help ASAP plz help me I just need to know what to do

There is a rule:

One input(x-value) can only have one output(y-value) in order to be a function.

If one input has more than one output, it is not a function.

(This doesn't apply to outputs, meaning that it's still a function when one output has more than one input, because it's the input that can have only one output)

For example, problem #1, the graph is a function because each input has only one output.

you can't solve x because it is 2 linear equation and you only have one equation