Simplify (3x^2y^-4)^2

1/6x^4y^8
1/9x^4y^8
y^8/9x^4
-6y^8/x^4

In two fractions have the same denominator but different numerators,which fraction is greater? give an example

The serenity and the mystic are sail boats. the serenity and the mystic start at the same point and travel away from each other in opposite directions. the serenity travels at 16 mph and the mystic travels at 19 mph. how far apart will they be in 3 hours?

You eat $0.85 for every cup of hot chocolate you sell. how many cups do you need to sell to earn $55.25