Combine the like terms to create an equivalent expression:
{-k-(-8k)}−k−(−8k)
Apply PEMDAS (Parentheses, Exponentiation, Multiplication & Division, Addition & Subtraction), and remember operations at the same level (e.g. + -) are performed left to right:
(showing lots of steps, most of which you can do in your head w/practice)
{-k-(-8k)}−k−(−8k)
= { 7k } -k - (-8k)
= 7k - k - (-8k)
= 6k - (-8k)
= 6k + 8k
=