Factorise-the-expression-9x-4-1-x-4-2-

Question Number 7511 by Obenfo last updated on 01/Sep/16

Factorise the expression 9 x^{4} + \frac{1}{x^{4}} + 2 .

Answered by sandy_suhendra last updated on 01/Sep/16

b e c a u s e {(3 x^{2} + \frac{1}{x^{2}})}^{2} = 9 x^{4} + 6 + \frac{1}{x^{4}}

s o 9 x^{4} + 2 + \frac{1}{x^{4}} = {(3 x^{2} + \frac{1}{x^{2}})}^{2} - 4 = (3 x^{2} + \frac{1}{x^{2}} + 2) (3 x^{2} + \frac{1}{x^{2}} - 2)