Ma poate ajuta si pe mine cineva la c,d si e multumesc

c) (423-c):(671-111x3x2)=70
(423-c):(671-333x2)=70
(423-c):(671-666)=70
(423-c):5=70, 423-c=70x5, c=423-350=73
d) (1000-dx2-25x4):6=143
(1000-2d-100)=143x6
900-2d=858, 2d=900-858, 2d=42, d=42/2=21