Can someone check my algebra answers and help me with the problems I dont understand?

1. n^2-n-20/2n^2 times n^2+5n/n^2-25answer: n+4/2n2. (2x-6/21)/(5x-15/12)answer: 8/353. 5x-3/6 - x+3/6answer: 2x/3-14. 5x/26 - 2x/13answer: 1x/265. 3x^2/9x^5answer: 1/3x^36. (x^2+2x-15/4x^2)/(x^2-25/2x-10)answer: I'm not to sure but i think its x-3/2x^27. x+2/x/x-2/3xanswer: 3(x+2)/x-28. What values for x must be excluded in the following fraction?9/x-8answer: 89. x-13/x^2-x-12 + 3x-3/x^2-x-12answer: 4/x+3

All of your answers are correct except #3, it should be 2x/3

1. n + 72. 16/353. 4x4. you are correct5. you are correct6.3/7. Is the problem complete?7. 5/3x +28. you are correct9. (x - 12)/(5x^2)Edit: Apparently my answers don't match the rest. Take their word over mine. I'm going into 8th grade math nexxt year.