Answer:
Step-by-step explanation:
First, we need to look at the simpler equation. We see that the top equation is the simpler one.
y=-2x + 6
Now we plug that equation with the other one.
6x + 3(-2x + 6) = 18
6x -6x + 18 = 18
18 = 18
Since we see that 18 = 18. We know that this equation is a true equation. We can plug the y-variable in first and it will still be a true statement.
