Răspuns :
a+b = 100
a = 4 · b +5 => 4·b + 5 + b = 100
5·b = 100- 5 => 5·b = 95 => b = 95:5 => b = 19
a = 4·19 +5 = > a = 81
(a+b) = 81+19 = 100 , corect
a+b = 100
a = 4 · b +5 => 4·b + 5 + b = 100
5·b = 100- 5 => 5·b = 95 => b = 95:5 => b = 19
a = 4·19 +5 = > a = 81
(a+b) = 81+19 = 100 , corect