Given: | a = b | |
Multiply by a: | a2 = ab | |
Subtract b2: | a2 – b2 = ab – b2 | |
Factorise: | (a + b)(a – b) = b(a – b) | |
Divide by (a – b): | (a + b) = b | |
Substitute for b: | a + a = a | |
Simplify: | 2a = a | |
Divide by a: | 2 = 1 |
Clearly, this is impossible. So where’s the error?
Answers on a postcard, or in the comments