Answer: Y=-4x-18
Explanation: You need to get y by itself so you will move -4x to the other side by adding it on both side so it can cancel out on the side that it was originally which was the y side.
This will give you -y=4x+18
Now you need to make y become a positive so you will divide both side by -1 ( the 1 comes from in front of the y there is always an invisible 1 if there is no number in front of the letter (x,y,etc))
When you divide everything by -1 it will get you : y=-4x-18