Want to know how?
Let a=b.
Multiply both sides by a.
Now we have a^2=ab
Subtract b^2 from both sides.
Now we have a^2-b^2=ab-b^2
Factor.
(a+b)(a-b)=b(a-b)
Divide by (a-b).
a+b=b
But a=b, so
b+b=b
Simplify
2b=b
Divide by b
2=1
You’re welcome.
Edit: Congrats to LahDsai to finding the error. Yes, the proof technically divides by zero. Not sarcastic at all, nice job. Took me a little bit of my own time to find the error.
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But, If you do this simple trick it doesn’t [spoiler]2≠1[/spoiler]