( Y+2) + ( Y+4)+........+(Y+1994)=997000
(Y + Y + .... + Y ) + (2 + 4 + ... + 1994 ) = 997000
Y x 997 + [ (1994 + 2 ) x 997 : 2 ] = 997000
Y x 997 + 995 006 = 997000
Y x 997 = 997000 - 995 006
Y x 997 = 1994
Y = 1994 : 997
Y = 2.
Vậy Y = 2.
Hok tốt !