# Move Two Lines to make the equation correct

Move 2 lines (one short and the other long) from one side (either) to the other side of the = sign to make the equation correct. Cannot use "not equal to" sign. You must move 2 lines as stated. Some creative thinking may be needed.

Hint:

Think of letters

• Are all lines supposed to be the same length? Jan 20 at 0:11
• No. The lines are of the length as given in the image. Thanks Jan 20 at 12:42

Starting point

The Bekenstein-Hawking formula for the entropy of a black hole, $$S$$, in Planck units, is given by $$S = A/4$$ where $$A$$ is the area of the event horizon.
We may rewrite this equation as $$4 = A/S$$ or perhaps $$4-0 = A/S$$

Given that, we move the following (highlighted) lines

To the opposite sides of the equals sign to give

• "Move 2 lines (one short and the other long) from one side", but you moved from left and right side. is it okay like that?
– Oray
Jan 23 at 14:40
• @Oray My interpretation is that each line must move from one side to the other (but not necessarily originating from the same side). Although the phrasing in the question is a little ambiguous. Jan 23 at 14:45

4 - 0 = 9 - 5 That is, the 1 becomes a minus and the division also becomes a minus.

• It says to move two lines from one side of the equality sign to the other. Jan 20 at 6:02
• The way I see it, the division sign should become the minus on the left side, and the 1 should become the subtraction side on the other one.
– parz
Jan 20 at 12:40