Two times the length of the longest edge.
<h2>
Explanation:</h2>
We use an equation to say that two things are equal. An equation always has an equal sign "=". So an equation tells us that the left side is equal to the right side. In this case, we have the following equation:

So the only value that makes this equation to be true is 5, because:

For instance, let's choose another value, say, 8. So substituting:

Answer:
-20x+745. (expression). y= -20x+745 (Equation).
Step-by-step explanation:
Hope this helps.
x: the number or days.
y: the total number pictures that have been deleted.