Answer:
70x³ - 73x² - 155x + 168
Explanation:
Given
(5x - 7)(2x + 3)(7x - 8) ← expand the first pair of factors using FOIL
= (10x² + x - 21)(7x - 8)
Each term in the second factor is multiplied by each term in the first factor, that is
10x² (7x - 8) + x(7x - 8) - 21(7x - 8) ← distribute the 3 parenthesis
= 70x³ - 80x² + 7x² - 8x - 147x + 168 ← collect like terms
= 70x³ - 73x² - 155x + 168