Division by 0/Fallacies

Here are the list of mathematical error using division by 0.

3 = 1
Assume A = 1 and B = 1.

Then we know that A and B are equal:

$$a = b$$

$$a^2 = ab$$

$$(a-b)(a+b)+a = (a-b)ab+ab$$

$$(a+b)+a = ab$$

$$(2)+1 = (1)(1)$$

3 = 1