[tex] {8x}^{3} + 1 \\ = {(2x)}^{3} + {(1)}^{3} \\ = (2x + 1)( {(2x)}^{2} - 2x \times 1 + {(1)}^{2}) \\ = (2x + 1)( {4x}^{2} - 2x + 1)[/tex]
Hope you could get an idea from here.
Doubt clarification - use comment section.