Guys,

This probably is very silly question but might puzzle few ppl.
so who is first to answer ?

16-36+20 1/4 = 25-45+20 1/4
16-36+81/4 = 25-45+81/4
(4 -9/2)(sq) = (5-9/2) (sq)
4 -9/2 = 5 -9/2
4 =5

The square root of a^2 has 2 solutions : +a and -a.

So, when you take the square root of the 2 members of an identity, you should connect the solutions properly to still have an identity.

In fact, 4 - 9/2 = - (5 - 9/2)
4 - 4.5 = - (5 - 4.5)
- 0.5 = - (0.5)
- 0.5 = - 0.5 is correct.

Nice try,

Jean-Marie