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

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What goes through cities and fields, but never moves?

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Can you?

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Hint 2: I am environment-friendly.

Replace the question mark with the correct number in below Picture:

O_er_t_o_

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