Answer:
(x+2)(x+1)(4x+1)(4x-3)
Step-by-step explanation:
(4x² + 5x)² - 5(4x² +5x) - 6
= (4x² + 5x)² - 6(4x² +5x) + 1(4x² +5x) -6
= (4x² + 5x)(4x² +5x -6) +1 (4x² +5x -6)
= (4x²+5x-6)(4x²+5x+1)
= (4x² + 8x - 3x - 6)(4x² + 4x + x +1)
= (4x(x + 2) - 3(x + 2))(4x(x+1) +1(x+1))
= (x+2)(4x-3)(x+1)(4x+1)
