Everyone knows that 4 can never be equal to 5, but in this proof you can see it.If you think that there is any mistake you can point out.
Proof:
4=4 (all of us will agree, right?)
now multiply both sides with -5, we get
-20 = -20
or 16-36 = 25-45
by adding 81/4 both sides, we get
16-36+81/4=25-45+81/4
or (4-9/2)x(4-9/2) = (5-9/2)x(5-9/2)
Taking square root both sides, we get
(4-9/2)=(5-9/2)
__> 4=5
Hece, prooved