What are the x and y values for y=-3x and y=-x-2

Since  y  =  -3x     and     y  =  -x - 2     are both solved for y:

you can set them equal to each other:     -3x  =  -x - 2

To get all the x-terms to one side, add x to both sides:

                                                        -3x + x  =  -x + x - 2

                  Simplify:                                -2x  =  -2

                                                                  x  =  1

If x = 1:  y  =  -3x  -->  y  =  -3(1)  =  -3

if x = 1:  y  =  -x - 2  -->  y  =  -(1) - 2  =  -3    

Since you get the same answer in both equation, the point (1, -3) checks.     x  =  1        y  =  -3