Step-by-step explanation:
[tex](7x - 4)(8x + 4) \\ \\ = 7x(8x + 4) - 4(8x + 4) \\ \\ = 56 {x}^{2} + 28x - 32x - 16 \\ \\ = 56 {x}^{2} - 4x - 16[/tex]
