Question

Where am I wrong and Why?
2+2
= 4
= 4 - 9/2 + 9/2
= root [ (4 - 9/2)^2 ] + 9/2
= root [ 16 - 36 + (9/2)^2 ] + 9/2
= root [ -20 + (9/2)^2 ] + 9/2 = root [ 25 - 45 + (9/2)^2 ] + 9/2
= root [ (5 - 9/2)^2 ] + 9/2
= 5 -9/2 + 9/2
= 5

Answer 1

root [ (4 - 9/2)^2 ] + 9/2

You are wrong there because 4 - 9/2 = -1/2, while
\sqrt{(4-9/2)^2}=1/2