Răspunsuri

2014-04-04T18:00:33+03:00
A-b=5⇒a=5+b
(a+b)-5=40
a+b=40+5
a+b=45
5+b+b=45
5+2b=45
2b=45-5
2b=40
b=40:2
b=20
a= 5+20
a=25

2014-04-04T18:00:42+03:00
Notam numerele cu a si b
a - b = 5
(a+b) - (a-b) = 40 => a + b = 40 + 5 = 45
a - b = 5
a + b = 45 +
2a = 50 => a = 25
a - b = 5 => 25 - b = 5 => b = 20