Verified answer

[tex] - 4a \times 6b = - 24ab[/tex]

[tex]1.5c \times ( - 4d) = - 6cd[/tex]

[tex]6a - 5a + 8a - 7a = (6 - 5 + 8 - 7)a = (14 - 12)a = 2a[/tex]

[tex]9b + 12 - 8 - 4b = 4 + 5b[/tex]

[tex]( - 48.75 \div 3.9 + 8.2) \times ( - 4) \div ( - 0.2) = ( - 12.5 + 8.2) \times ( - 4) \div ( - 0.2) = - 4.3 \times ( - 4) \div ( - 0.2) = 17.2 \div ( - 0.2) = - 86[/tex]