You can you 72 which would make 2/8 18/72 and 3/9 24/72 which makes the sum 42/72.
(6)^-2 Is equivalent to 1/36
To solve first move the 98 to the other side by subtracting it from both sides. Then divide by - 1 on both sides to that the x^2 is no longer a negative. You are left with:

Now square root both sides to get

The two factors that make up 98 are 49 and 2. 49 can be square rooted. So we are left with these answers:

and
It weighs 24 ounces. I got this by multiplying 6 by 16 (number of ounces in a pound) and dividing by 4 (number of quarts in a gallon)