Answer:
B
Step-by-step explanation:
5x - 625[tex]x^{4}[/tex] ← factor out 5x from each term
= 5x(1 - 125x³) ← this factor is a difference of cubes and factors in general as
a³ - b³ = (a - b)(a² + ab + b²) , then
1 - 125x³
= 1³ - (5x)³
= (1 - 5x) (1² + 5x(1) + (5x)² )
= (1 - 5x) (1 + 5x + 25x²)
Then
5x - 625[tex]x^{4}[/tex] = 5x(1 + 5x + 25x²)
