Răspuns :
a-b=72 si (a-c)-(b+c)=18
(a-c)-(b+c)= a-c-b-c= a-b-2c
a-b-2c=18
72-2c=18
2c=54
c=27
a - b = 72
( a - c ) - ( b + c ) = 18
a - c - b - c = 18
( a - b ) - 2 c = 18
72 - 2 c = 18
2 c = 72 - 18
2 c = 54
c = 54 : 2
c = 27
a-b=72 si (a-c)-(b+c)=18
(a-c)-(b+c)= a-c-b-c= a-b-2c
a-b-2c=18
72-2c=18
2c=54
c=27
a - b = 72
( a - c ) - ( b + c ) = 18
a - c - b - c = 18
( a - b ) - 2 c = 18
72 - 2 c = 18
2 c = 72 - 18
2 c = 54
c = 54 : 2
c = 27