Răspuns :
a |-----|-12-| } 30
b |-----|
30 - 12 = 18 ( două segmente egale )
18 : 2 = 9 ( un segment )
a = 9 + 12
a = 21
b = 9
b |-----|
30 - 12 = 18 ( două segmente egale )
18 : 2 = 9 ( un segment )
a = 9 + 12
a = 21
b = 9
a - b = 12 => a = b + 12
a + b = 30
__________
a, b = ?
b + 12 + b = 30
2b + 12 = 30
2b = 30 - 12
2b = 18
b = 18 : 2
b = 9
a = 9 + 12
a = 21
verific : 9 + 21 = 30 ✔
21 - 9 = 12 ✔
a + b = 30
__________
a, b = ?
b + 12 + b = 30
2b + 12 = 30
2b = 30 - 12
2b = 18
b = 18 : 2
b = 9
a = 9 + 12
a = 21
verific : 9 + 21 = 30 ✔
21 - 9 = 12 ✔