calculati 2a+7b+3c stiind ca a+2b=198si b+c=532. 4a+18b+15c+18d stiind ca 2a+3b=50 si 4b+5c+6d=120

Răspuns :

Sistem:
2a+7b+3c              2(-2(532-c)+198)+7(532-c)+3c
a+2b=198     =>     a=-2(532-c)+198       
b+c=532                b=532-c

2(-2(532-c)+198)+7(532-c)+3c = 2(-1064+2c+198)+3724-7c+3c=-2128+4c+396+3724-7c+3c=1992