Step-by-step explanation:
[tex] = 10(1 - 7k) + 8(k + 9)[/tex]
Sort the expression in descending order....
[tex] = 10( - 7k + 1) + 8( k + 9)[/tex]
Now multiply....
[tex] = - 70k + 10 + 8k + 72[/tex]
Organize the similar terms...
[tex] = - 70k + 8k + 10 + 72[/tex]
[tex] = - 62k + 82[/tex]
hope it helped !!!