Question

Could someone please help check the answer to these few questions, and make sure they are right?

1. Simplify x over 4 x + x^2
is the answer 1 over x + 4; where x =/ -4, 0

2. Simplify x + 7 over x^2 + 4x - 21
is the answer 1 over x - 3


3. -14x^3 over x^3 - 5x^4
is the answer -14 over 5x - 1


4. Simplify x^2 + 3x - 21 over x + 2
is the answer x - 5


5. Multiply k + 3 over 4k - 2 times (12k^2 + 2k - 4)
is the answer 3(k + 3) over 3k + 2

Thank you !!!