How do you solve x plus 3y equals 6?

Answer 1

You can't. From that much information, you can't figure out the values for both 'x' and 'y'.

All you can tell is that whatever they turn out to be:

x = 6 - 3y

and

y = x/3 - 2.

In order to calculate what 'x' and 'y' both are, you need another equation besides

x + 3y = 6.

There's nothing wrong with that one, but you need one more.

You need the same number of equations as the number of unknowns.