SOLUTION: there is an error in this problem... can you tell me where it is?? =\ x=2 x(x-1) = 2(x-1) x^2-x = 2x-2 x^2-2x = x-2 x(x-2) = x-2 x=1 Thanks for you help.... jj

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: there is an error in this problem... can you tell me where it is?? =\ x=2 x(x-1) = 2(x-1) x^2-x = 2x-2 x^2-2x = x-2 x(x-2) = x-2 x=1 Thanks for you help.... jj      Log On


   

Question 149528: there is an error in this problem... can you tell me where it is?? =\
x=2
x(x-1) = 2(x-1)
x^2-x = 2x-2
x^2-2x = x-2
x(x-2) = x-2
x=1
Thanks for you help.... jj
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
It's the second to last step. The error that occurs is a division by zero.

If x=2, then x-2 is really 2-2=0

So x-2=0


So x%28x-2%29=x-2 is really x%280%29=0.

In this step, there is a division by x-2 to get x%28x-2%29%2F%28x-2%29=%28x-2%29%2F%28x-2%29


However, since x-2=0, this means that this happens x%280%29%2F%280%29=%280%29%2F%280%29

But you cannot divide by zero. So this is where the flaw occurs. This is a common fallacy in the "proofs" of odd statements like 1=2 or 0=1. Or in this case, you're "proving" that x=1=2.