how do you substitute these system of equations

Question

1.y=-3x-3
y=3x-3

2.y=4x-6
y=x

thank you!

Answer 1

1. take the value of y from the first, and plug it into the second.
(-3x-3) = 3x-3
0 = 6x
x = 0
y = -3

2. do it the other way, since the second is so simple.
x = 4x-6
3x = 6
x=2
y=2

Answer 2

1.y=-3x-3
y=3x-3
try
-3 x - 3 = 3 x - 3
0 = 6 x
x = 0
then y = -3
=======================
2.y=4x-6
y=x
try
x = 4 x - 6
3 x = 6
x = 2
then
y = 2