Instruction: Write a single fraction with one numerator and one denominator.

Problem#1:

1/x + 1/y

I think the answer should be x+y/xy, yes?

Problem #2:

(5a^-1 + 2b^-1) / (3a^-2 - 2b^-2)

I think the answer should be (3a-b) / 5, yes?

Problem #3:

[9-(1/y^2)] / [9+ (6/y) + (1/y^2)]

I think the answer should be 1 / (6/y), yes?

Problem #4 says to factor completely:

18y^3 + 48y^2 + 42y

I think the final answer should be 6y(3y^2 + 8y + 7), yes?

Thank you!