3 ms·
assume: x = y then: xx = xy and then: xx - yy = xy - yy factor: (x+y)(x-y) = y (x-y) cancel: x+y = y replace: x + x = x simplify: 2 * x = x there
by drallison 16y ago
assume: x = y
then: xx = xy
and then: xx - yy = xy - yy
factor: (x+y)(x-y) = y (x-y)
cancel: x+y = y
replace: x + x = x
simplify: 2 * x = x
therefore: 2 = 1
QED