You can put this solution on YOUR website! This is a very creative problem. Usually when they want you to find a mystery number, they call the mystery number x. They could really use any symbol, but e is very unusual.
I like to think of minus signs as belonging to the number that follows them.
(If I do not see a number, it is an invisible number 1).
So what I see is:
Applying the distributive property (it make look backwards to you but equal signs are two way streets):
That is what I see. What I write is: -->
Then I add those two negative numbers. I know that
So, the next transformed equation I write is:
and that's when I realize that e=2, but I humor the teacher by writing next -->
to show that dividing both sides of the equal sign by (-10) I get an equivalent equation, and that (-20) divided by (-10) is 2, just as 20 divided by 10 is 2.
