Question 829589
(1/9 h^6 + 6/7 h^2) + (3/4 h^6-1/28h^2)
(1/9 + 3/4)h^6 +(6/7 -1/28)h^2
Use 36 as a common denominator for the h^6 coefficient
(4/36 + 27/36)h^6 + (6/7 -1/28)h^2
No use 28 as the common denominator for the h^2 coefficient
(4/36 + 27/36)h^6 + (24/28 -1/28)h^2
{{{(31/36)h^6 + (23/28)h^2}}}
One could factor out h^2 to get
{{{h^2( (31/36)h^6 + (23/28) )}}}
This checks out on wolframalpha.
Check http://www.wolframalpha.com/input/?i=%281%2F9+h^6+%2B+6%2F7+h^2%29+%2B+%283%2F4+h^6-1%2F28h^2%29

Let me know if you need further assistance. tutorLinnWilson.jimdo.com