Question

What is the solution to the system of equations `x=y-3, x+3y=13`?

Answer 1

`x=1, y=4`.

Explanation:

Here's one of many ways of solving this system. Since we are already told that `x=y-3` from the first equation, just plug in `y-3` everywhere you see an `x` in the second equation.

So the second equation becomes `(y-3)+3y=13`. Solve this for `y` to get `y=4`.

Then, go back to the first equation that says `x=y-3` and plug in `y=4`. So `x=1`.

Check your work by plugging in the values. `1=4-3` and `1+3(4)=13`, so we are right.