Solve by substitution. ( show work)
x=y
x-3y=4
[i know the answer is (-2,2) but idk how to get there]

First, let's find y by substituting x for what x is equal to, so that we will only have one variable and we can solve the equation.

x = y    Given
x - 3y = 4    Given
y - 3y = 4   Substitute x for y, because x = y
-2y = 4    Subtract
y = -2   Divide

Now, to find x, we need to substitute our value for y back into the original equation.

x = y
x = -2   Substitute -2 for y, since y = -2

The correct answer is (-2,-2).

Hope this helps!