Explanation:
= ( 5x - 1 ) ( 3x + 2 ) ( 9x - 4 )
= 5x ( 3x + 2 ) - 1 ( 3x + 2 ) ( 9x - 4 )
= 15x² + 10x - 3x - 2 ( 9x - 4 )
= ( 15x² + 7x - 2 ) ( 9x - 4 )
= 15x² ( 9x - 4 ) + 7x ( 9x - 4 ) - 2 ( 9x - 4 )
= 135x³ - 60x² + 63x² - 28x - 18x + 8
= 135x³ + 3x² - 46x + 8