Question

our teacher handed us this

$a=b\\ a^2 = ab\\ a^2-b^2 = ab-b^2\\ (a+b)(a-b) = b(a-b)\\ a+b = b\\ since a=b\\ 2b=b\\ 2=1$ 0_0


we are asked to find an error.

Answer 1

Answer:

2b=b

then b can't be divided

the correct process is 2b-b=0

. b=0