How do I factor this expression completely?

4x2(x2+1)(x+2)3+36(x2+1)2(x+2)4

1 Answer
Jun 30, 2016

4x2(x2+1)(x+2)2+36(x2+1)2(x+2)4=4(x2+1)(x+2)2(9x4+36x3+46x2+36x+36)

Explanation:

It is observed that 4x2(x2+1)(x+2)2 and 36(x2+1)2(x+2)4 have common factors

4, (x2+1) and (x+2)2.

Note that for (x2+1) and (x+2), we have selected the minimal power of these among two expressions. Similarly between 4 and 36, 4 is common factor.

Hence taking out these common factors, we get

4x2(x2+1)(x+2)2+36(x2+1)2(x+2)4

= 4(x2+1)(x+2)2[x2+9(x2+1)(x+2)2]

= 4(x2+1)(x+2)2[x2+9(x2+1)(x2+4x+4)]

= 4(x2+1)(x+2)2[x2+9(x4+4x3+4x2+x2+4x+4)]

= 4(x2+1)(x+2)2(9x4+36x3+46x2+36x+36)