You solve it by factoring each of the expressions and cancelling common factors.

For example, 9x^{2} - 4 factors into (3x - 2)(3x+2). Also, 27x^{4} + 8x factors into (x)(27x^{3} + 8) which contains a sum of cubes, so that factors further into (x)(3x+2)(9x^{2} - 6x + 4).

Hope this helps,
Stephen La Rocque.

Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.