Find the mistake in the below maths equations

A = 2
A(A-1) = 2(A-1)
A2-A = 2A-2
A2-2A = A-2
A(A-2) = A-2
A = 1

What does this rebus riddle means ?

On a magical land of Mexico , all the animal in the land are rational.

There are 10 tigers and one goat.
Tiger can eat goat but since it's a magical land , the tiger who eats the goat , turns into goat and then can be eaten by the remaining tiger(s).

If we leave them for some time then how many goat and tiger will be there , when we come back ?

What four weights can be used to balance from 1 to 30 pounds?

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While Bella does not know the answer, do you ?

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How many sides does a circle have?

How can you leave a room with two legs and return with six legs?

What part of Turkey has the most feathers?