18 = 3 (3x - 6)

Step by step

Start by multiplying 3 times 3x to get 9x. Then multiply 3 times - 6 to get - 18

After that your equation is 18=9x-18

Then your going to add 18 to each side so your equation should be 36=9x

Then devide each side by 9 so the answer will be x=4