Arunning faucet can use 1200 liters per hour. what is the rate or water usage in liters per minute

1200/60 = 20 liter per minute

So first multiply:
6x -6 = 9x + 18
then we "move the numbers ":
6x-9x= 18 +6
the positive and negative signs will change. anyways, now combine the like terms:
-3x= 24
now we divide 3 from both sides in order to isolate x:
-3÷3x= 24÷3
-x = 8
noq divide the negative from both sides:
x= -8