Solutions to systems of linear equations are any points that satisfy all equations in the system. They are usually listed as a coordinate but they can also be written in a different way if solving a word problem or when required by the instructions. An easy way to check if a point is a solution to the system is to plug the value into all of the equations and see if they result in true statements. If it does not, that means that the point is not a solution to the system of linear equations.
A system of linear equations can either have infinite solutions, no solutions or one solution. It can only have infinite solutions when all of the lines have the same slope and y-intercept, but they are written in different forms. Parallel lines are when the lines have the same slope but different y-intercepts, so they never intersect. Lines have one solution if they have different slopes.