Answer:
x=7
Explanation:
You need to bring 9x to the right side and bring '-ll' to the left side so it will be 11+10 = 12x-9x. Then you calculate 11+10, which is 21, then you subtract 12x to 9x. Then it will be 21 = 3x. Lastly, you divide 3 on both sides of the equation and get x to be 7!