Question

where is the mistake in it? ​

Answer 1

Itz correct !!! Good job

Answer 2

many many mistakes are there in this question first of all in the second line this is given that a square minus b square is equal to to ab minus b square. in this line if if a is equal to b then the value of a square minus b square will be zero at this point.

and again if a minus b is equal to zero then if we divide any number bi a minus b then the number will automatically become infinity.