Answer:
The product is the difference of squares is 
Step-by-step explanation:
Explanation
- The given expression is (x y-9)(x y+9).
- We have to multiply the given expression.
- Square the first term xy. Square the last term 9 .

-- The trains start moving at the same time.
-- The space between them is initially 252.5 miles.
-- They reduce the distance between them at the rate of (124.7+253.5)=378.2mph.
-- It will take them (252.5 / 378.2) = 0.6676 hour to meet.
That's 40min 3.49sec .
-- After tooting and puffing toward each other for 8 minutes, they still have <em>32min 3.49sec</em> to go before they meet each other. We're all hoping that they're on different tracks.
Answer: y=0
Step-by-step explanation: i think this is right