# Can 2=1 ?

If A=B

Multiply by A on both sides, you get A²=AB.

Subtract B² from both sides,
you get A²-B²=AB-B².

Factor both sides, you get (A+B)(A-B)=B(A-B).

Divide by (A-B) on both sides, you get A+B=B.

Because A=B, therefore B+B=B,

If 2B=B, then 2=1.

Answer: The problem is when you try to divide both sides by (A-B).

Because A=B, therefore (A-B)=0.

You can't divide any equation by zero.