[Slight]

Originally posted by blowmeetheclown
Let a=b.
a*a=a*b,
a^2=ab,
a^2+a^2=ab+a^2,
2a^2=a^2+ab,
2a^2-2ab=a^2+ab-2ab,
2(a^2-ab)=a^2-ab,
2a(a-b)=a(a-b),
2a=a,
2=1.

...,
2a(a-b)=a(a-b),
2a(0)=2(0),
0=0;