Solve: 108n^4 - 252n^2 +147

108n^4 - 252n^2 +147

Nothing to solve, I can try to factor, gcf is at least 3:

3*(36n^4 - 84n^2 + 49)

36n^4 is square and so is 49

IS the middle term: 2*6*n^2*7 ???

2*6*n^2*7 = 84n^2

Yes, it is. So:

3*(6n^2 - 7)^2

Note that: (a - b)^2 = a^2 - 2*a*b + b^2

3(36n^4 - 84n^2 + 49)
3(6n^2 - 7)(6n^2 - 7)
3(6n^2 - 7)^2

proof:
http://www.wolframalpha.com/input/?i=108…