Hello!
I believe you want me to solve 21.
In this equation, our first step will be to distribute. In the example, 2 was distributed to k and 5.
When we distribute, we multiply the number outside of the parentheses to all the terms within.
In question 21, you are going to be distributing 7 unto c and 4.
Therefore, you will have 7c + 28 - 19 = -26
If you need help for solving the rest of the equation, just comment!
Hope I helped!
-Mary :)