Answer:
(B.) -7k+21
Step-by-step explanation:
Your first step should be to solve your original expression.
-7×6=-42
-7x-3=21.
You're finishing numbers are -42 and 21.
-7k can equal to -42 if k is 6.
So we can use -7k
Since -7x-3=21, Then the answer would have to be:
-7k+21.