What is the error? Why erroneous?

[needimprovement]

Can anyone spot the error in this fallacy

 

<prepared>a + b = t

<prepared>(a + B )(a - B ) = t(a - B )

<prepared>a^2 - b^2 = ta - tb

<prepared>a^2 - ta = b^2 - tb

<prepared>a^2 - ta + (t^2)/4 = b^2 - tb + (t^2)/4

<prepared>(a - t/2)^2 = (b - t/2)^2

<prepared>a - t/2 = b - t/2

<prepared>a = b

 

Therefore all numbers are the same!

Edited September 15, 2010 by needimprovement

[TonyMcC]

surely line 2 should be ( a+B )( a-B )= a^2 - B^2 ?

Edited September 15, 2010 by TonyMcC

[D H]

Can anyone spot the error in this fallacy

Right here.

 

 

<prepared>(a - t/2)^2 = (b - t/2)^2

<prepared>a - t/2 = b - t/2

 

 

[the tree]

You've really got to stop posting such embarrassingly easy 'puzzles'.

[needimprovement]

You've really got to stop posting such embarrassingly easy 'puzzles'.

Thank you for your comment.