alright,
Let's say n=m,
Then nm=n^2
Then we just choose to subtract m^2 from both sides (it doesn't affect the equation) nm-m^2=n^2-m^2
Then we got m(n-m)=(n-m)(n+m)
Let's go on and divide with n-m and we have
m(n-m)/(n-m)=(n-m)(n+m)/(n-m) which gives us
m = n+m,
since n=m this means that m=2m
If we divide by m both sides then 1=2.
So what's wrong with this???
Let's say n=m,
Then nm=n^2
Then we just choose to subtract m^2 from both sides (it doesn't affect the equation) nm-m^2=n^2-m^2
Then we got m(n-m)=(n-m)(n+m)
Let's go on and divide with n-m and we have
m(n-m)/(n-m)=(n-m)(n+m)/(n-m) which gives us
m = n+m,
since n=m this means that m=2m
If we divide by m both sides then 1=2.
So what's wrong with this???