posted by Robert .
Indicate and explain the logical error in the following set of algebraic expressions
square both sides to get a^2=b^2
Since a=b, then a^2=a*b
Subtract b^2 from both sides a^2-b^2=a*b-b^2
Factor both sides: (a+b)(a-b)=b(a-b)
Divide both sides by (a-b)
Divide by b
You said " Divide both sides by (a-b) " , but a = b
so you are dividing by zero, which is a no-no in math .