Answer:
A,) 20
Explanation:
First, I am assuming that the problem is 5k = 100, not "5k = 100k =" as it was written.
We need to end up with "k equals some number." This is called solving for k. In order to do this we need to have k by itself. We look at the problem and ask, "what is preventing k from being by itself?" In this case k has a "times 5" with it. How can we get rid of that? Well we can do the opposite of "times 5," and that is to divide the left side by 5. That leaves k by itself which is exactly what we need. But if do something to one side of an equation, we need to do it to the other side for the equation to still be true. So in this case we also have to divide the right side by 5 also, which gives us 20 on the right side. So in our original problem:
5k = 100
Divide both sides by 5 and we have the answer:
k = 20