How do you factor 64x3+8=0?

1 Answer

8(2x+1)(4x22x+1)=0

Explanation:

This is a sum of cubes, since both 64x3=(4x)3 and 8=(2)3 are cubed terms.

Differences of cubes factor as follows:

a3+b3=(a+b)(a2ab+b2)

In 64x3+8, we see that a=4x and b=2, so

64x3+8=0

(4x+2)((4x)24x(2)+(2)2)=0

(4x+2)(16x28x+4)=0

8(2x+1)(4x22x+1)=0