Q:

How do I modify a system of equations to receive unlimited solutions (SAT Question)

I am sorry that I don't have a specific question (it was on my sat make-up) but I remember a question that went something like 3x + 2y = 26 and another part of the system of equations that I don't remember. The question asked to modify the second part of the system of equations in order to give the system infinite solutions. How should I approach a question like this? 

A:

If there are two equations, and one is a multiple of the other, then there are infinitely many solutions to the system.
In general, if there are $n$ equations in $n$ unknowns, there will be infinitely many solutions if one or more of the equations is a linear combination of the others. (However, if any two equations are inconsistent, then no solution to the system exists.) 

