(Remember: as long as you perform the same operation on both sides an equation stays equal.)
| Assume: | x = 2 |
| Multiplying by 4: | 4x = 8 |
| Subtracting 6x: | –2x = 8 – 6x |
| Adding 1: | –2x + 1 = 9 – 6x |
| Adding x2: | x2 – 2x +1 = x2 – 6x + 9 |
| Factorising: | (x – 1)2 = (x – 3)2 |
| Taking square roots: | x – 1 = x – 3 |
| Subtracting x: | – 1 = – 3 |
| Changing signs: | 1 = 3 |
Q.E.D.