would some one please check these for me

Question

1. divide x^2-36y^2 over 5x^2+30y divide (x^2-6xy)

A: x+6y over (5x)(x^2+6y)

2. Add. Express your answer in simplest form.
2x 0ver x^2+15x+54 + 4over x+6

A: 6 over x+9

3. solve: (9 over x-5) -1= 8 over x+5
A: -10 and 11

This one I am having problems with a lot

4. Simplify 6/8 over 2/18
this is what I did would you please see if I did this right

6/8
over
2/18

6/8
over
1/9

9*6/8
9+3/4
9*4/4+3/4
36/4+3/4
39/4

5. Subtract 7 over y-3 -1 over y+1

A: is 2(3y+5) over (y-3)(y+1)

6. What values for x must be excluded in the following fraction?

x+2 over x^2-9x+14

A: 2 and 7

7. Solve. x over 3 - x over 4 =4

A: x=48

8.Solve. 7 over x-9 + 4 = 3 over x-9

A: 8 and 9

9.solve x+1 over 18 = 1 over 3

A: 5

10.If one-half a number is subtracted from five-sixths of the number, the difference is 6. Find the number.

A: 5/6n - 1/2n=6
n= 18

I checked just this one since you were having so much trouble with it. See below.
4. Simplify 6/8 over 2/18
this is what I did would you please see if I did this right

6/8
over
2/18

6/8
over
1/9

9*6/8 OK to here
9+3/4 You changed the * sign to + sign. Should be 9*3/4 = 27/4
9*4/4+3/4
36/4+3/4
39/4
I would have done it this way.
(6/8)/(2/18) =
(6/8)*(18/2) =
(3/4)*(9) = 27/4