Question:
Mark (✓) against the correct answer:
8x3 − 2x = ?
(a) (4x − 1)(2x − 1)x
(b) (2x2 + 1)(2x − 1)
(c) 2x(2x − 1)(2x + 1)
(d) none of these
Solution:
(c) 2x(2x − 1)(2x + 1)
$8 x^{3}-2 x$
$=2 x\left(4 x^{2}-1\right)$
$=2 x\left((2 x)^{2}-1^{2}\right)$
$=2 x(2 x-1)(2 x+1)$