Evaluate
Since at numerator and denominator becomes zero.
∴ it is of form.
∴ By factor theorem, is a factor of both numerator and denominator.
is also a factor of both numerator and denominator because irrational roots occur in pairs.
So, x2 -2 is a factor of both numerator and denominator.
By long division method, dividing numerator and denominator by x2 -2.
x9 - 3x8 + x6 - 9x4 - 4x2 - 16x + 84 = (x2 -2) (x7 - 3x6 + 2x5 -5x4 + 4x3 -19x2 +8x - 42) and x5-3x4 -4x + 12 = (x2 -2) (x3 - 3x2 + 2x -6)
∴