Help me pls class ends in an hour

Compare the subtraction problems 6/8 - 5/8 = 1/8 and 6/9 - 7/9 = 1/9 why is the answer to the first problem positive and the answer to the second problem negative

Aswimming pool measures 22ft by 12ft and is 4ft deep. if the pool is being filled at 2.5 cubic ft per minute, how long will it take to fill the pool?

Select the correct answer from each drop-down menu. a system of equations and its solution are given below. system a complete the sentences to explain what steps were followed to obtain the system of equations below. system b to get system b, the equation in system a was replaced by the sum of that equation and times the equation. the solution to system b the same as the solution to system a.]