metamath/valid/algebra-manipexpr-apbeq2cceqiacpbceqm2.mm (16 lines of code) (raw):

${ algebra-manipexpr-apbeq2cceqiacpbceqm2.0 $e |- ( ph -> A e. CC ) $. algebra-manipexpr-apbeq2cceqiacpbceqm2.1 $e |- ( ph -> B e. CC ) $. algebra-manipexpr-apbeq2cceqiacpbceqm2.2 $e |- ( ph -> ( A + B ) = ( 2 x. C ) ) $. algebra-manipexpr-apbeq2cceqiacpbceqm2.3 $e |- ( ph -> C e. CC ) $. algebra-manipexpr-apbeq2cceqiacpbceqm2.4 $e |- ( ph -> C = _i ) $. $( (Contributed by Stanislas Polu, 14-Sep-2020.) $) algebra-manipexpr-apbeq2cceqiacpbceqm2 $p |- ( ph -> ( ( A x. C ) + ( B x. C ) ) = -u 2 ) $= ( caddc co cmul c2 cneg adddird ci oveq12d 2cnd a1i 2cn wcel ax-icn mulassd cc oveq1d oveq2d ixi oveq2i wceq neg1cn mulm1i mulcomli syl5eq eqtrd 3eqtrd c1 eqtr3d ) ABCJKZDLKZBDLKCDLKJKMNZABCDEFHOAUSMDLKZPLKMDPLKZLKZUTAURVADPLGI QAMDPARHPUDUAAUBSUCAVCMPPLKZLKZUTAVBVDMLADPPLIUEUFAVEMUPNZLKZUTVDVFMLUGUHVG UTUIAVFMUTUJTMTUKULSUMUNUOUQ $. $}