a + b + c = 198; b - c = 123
Din relatia: b - c = 123 deducem ca: b = c + 123
a + b + c = 198
a + ( c + 123 ) + c = 198
a + 2 x c = 198 - 123
= 2 a + c + 123 + 3 c =
= 2 a + 4 c + 123 =
= 2 ( a + 2 c ) + 123 =
= 2 × 75 + 123 =
= 150 + 123 =
= 273
a+b+c=198
c=b+123
a+2b+123=198
a+2b=198-123=75
a+2b=75
75/=25
a=25
b=123+25=148
c=25
2a+b+3c
2x25+148+3x25 =50+148+75=273