According to my logic, $1=(-1)$, $2=(-2)$, $3=(-3)$, etc. This can't be right but please tell me where I went wrong.
$$\begin{array}{l} {\rm{Suppose}}\\ x = \left( { - x} \right)\\ {x^2} = {\left( { - x} \right)^2}\\ {x^2} = {x^2}\\ \sqrt {{x^2}} = \sqrt {{x^2}} \\ x = x \end{array} % MathType!MTEF!2!1!+- % faaagCart1ev2aaaKnaaaaWenf2ys9wBH5garuavP1wzZbqedmvETj % 2BSbqefm0B1jxALjharqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0x % bbL8FesqqrFfpeea0xe9Lq-Jc9vqaqpepm0xbba9pwe9Q8fs0-yqaq % pepae9pg0FirpepeKkFr0xfr-xfr-xb9Gqpi0dc9adbaqaaeGaciGa % aiaabeqaamaabaabaaGceaqabeaacaqGtbGaaeyDaiaabchacaqGWb % Gaae4BaiaabohacaqGLbaabaGaamiEaiabg2da9maabmaabaGaeyOe % I0IaamiEaaGaayjkaiaawMcaaaqaaiaabofacaqGXbGaaeyDaiaabg % gacaqGYbGaaeyzaiaabccacaqGIbGaae4BaiaabshacaqGObGaaeii % aiaabohacaqGPbGaaeizaiaabwgacaqGZbaabaGaamiEamaaCaaale % qabaGaaGOmaaaakiabg2da9maabmaabaGaeyOeI0IaamiEaaGaayjk % aiaawMcaamaaCaaaleqabaGaaGOmaaaaaOqaaiaadIhadaahaaWcbe % qaaiaaikdaaaGccqGH9aqpcaWG4bWaaWbaaSqabeaacaaIYaaaaaGc % baWaaOaaaeaacaWG4bWaaWbaaSqabeaacaaIYaaaaaqabaGccqGH9a % qpdaGcaaqaaiaadIhadaahaaWcbeqaaiaaikdaaaaabeaaaOqaaiaa % dIhacqGH9aqpcaWG4baaaaa!5D90! $$
You start with assuming that $ x = (-x)$. That possible, but if we solve this we get $$x = -x$$ $$x + x = 0$$ $$2x = 0 $$ $$ x = 0 $$ So $x = 0$. Now you can see why the rest holds.