Answer:
(1 - 4x)³
Explanation:
The first 2 terms are a difference of cubes and factor in general as
a³ - b³ = (a - b)(a² + ab + b²), thus
1 - 64x³
= 1³ - (4x)³
= (1 - 4x)(1 + 4x + 16x²)
Thus
1 - 64x³ + 48x² - 12x ← factor out 12x from each of the 2 terms
= (1 - 4x)(1 + 4x + 16x²) + 12x(4x - 1) ← factor out - 1 from (4x - 1)
= (1 - 4x)(1 + 4x + 16x²) - 12x(1 - 4x) ← factor out (1 - 4x) from the terms
= (1 - 4x)(1 + 4x + 16x² - 12x)
= (1 - 4x)(1 - 8x + 16x²) ← perfect square
= (1 - 4x)(1 - 4x)²
= (1 - 4x)³ ← in factored form