Given certain information, what is the value of x4-y4? got a question off of brilliant that is boggling my mind for some reason. anyone got some insight?

Well right off the bat, I can see a good reason why it should boggle.

If (x+y)=6 and (x-y)=2, then (x+y)(x-y) would be 12. It can't be 20.

The first 4 lines on the paper are inconsistent, so the question in the 5th line can't be calculated.

Another possible source of uncertainty (for us, anyway) is the remarkable similarity between the way you write ' Y ' and the way you write ' 4 ' . For example, look at the ' Y⁴ ' (I think ...) in the last line.

the answer is 13 cm