Answer:
You can substitute the x value of coordinate (x,y) in the equation. If the outcome = the y value in the coordinate (x,y), then you have determined it to be on the system of linear equations.
Explanation:
Point P has a coordinates: ( Px , Py ).
You can choose which value is easy to substitute. Eighter start with the Py or you could start with the Px. It could save you time if you pick the right one for the job.
If you want to verify if any point is valid in any (linear) equation(s), you can:
a) substitute the x value of coordinate (x,y) in the equation, and if the outcome has the same value as y in the coordinate (x,y), then that point is a valid solution of the (linear) equation.
b) substitute the y value of coordinate (x,y) in the equation, and if the outcome has the same value as x in the coordinate (x,y), then that point is a valid solution of the (linear) equation.