if you mean that 3x+3=0 then x should equal 0
7x20=140. 7x2000=14000. The only thing that changes the product of these numbers is the amount of zeros behind the 2. Since the only two numbers that affect the answer is the 7 and the 2. (7x2=14). The number of zeros behind the 2 affect how many zeros will be included in the product.
So you first make 1 7/9 into 16/9
then you do 16/9 - 4/9 which equals to 12/9 then you simplify and get 4/3 then simplify again into 1 1/3