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If, a=b
Then,
a^2=ab
=>a^2-b^2=a^2-ab
=>(a+b)(a-b)=a(a-b)
=>a+b=a
=>a+a=a
=>2a=a
=>2=1
I know there is a mistake in this calculation. What's that and please give me a logic behind that mistake.

NABILA wrote: ↑

Sat Dec 15, 2018 6:53 pm

If, a=b
Then,
a^2=ab
=>a^2-b^2=a^2-ab
=>(a+b)(a-b)=a(a-b)
=>a+b=a

In the last line you divided by zero (as $a=b$).
It is not defined in Mathmatics.Thats the mistke.