Răspuns :
14a-7b=5
7(2a - b) = 5
2a - b = 5/7 /x(-1)
b - 2a = - 5/7
9b - 18a - 4/5 =
9( b - 2a) - 4/5 =
9 x (-5/7) - 4/5 =
-45/7 - 4/5 =
( - 225 - 28)/35 =
- 253 /35
14a-7b=5
7(2a - b) = 5
2a - b = 5/7 /x(-1)
b - 2a = - 5/7
9b - 18a - 4/5 =
9( b - 2a) - 4/5 =
9 x (-5/7) - 4/5 =
-45/7 - 4/5 =
( - 225 - 28)/35 =
- 253 /35