Would someone please check these answers?

Question

Simplify. 3/x-5+1/1-4/x-5
For this answer I got: x-2/x-9

Divide. x^2-49y^2/6x^2+42y/(x^2-7xy)
For this answer I got: (x+7y)/6x(x^2+7y)

Add. Express your answer in simplest for. x/6+3x/6
For this answer I got: 2x/3
Please check my answers. Thank you.

Would someone please check these answers?
Simplify. 3/x-5+1/1-4/x-5
For this answer I got: x-2/x-9

Assuming that you have no typos, deal with like terms first.
3/x - 4/x = -1/x
1/1 = 1
-5+1-5 = -9
This gives me -1/x -9

Divide. x^2-49y^2/6x^2+42y/(x^2-7xy)
For this answer I got: (x+7y)/6x(x^2+7y)

Add. Express your answer in simplest for. x/6+3x/6
For this answer I got: 2x/3
Please check my answers. Thank you.

Unless the plus sign is supposed to be negative, you will not get 2x/3.

Because of apparent typos, I am not even going to deal with the division problem. However, I hope what I did helps. Thanks for asking.