tolong dibantu yaa makasih

A.
Keliling = (x + 2) cm + (x + 1) cm + (x + 2) cm
Keliling = (x + x + x + 2 + 1 + 2) cm
Keliling = (3x + 5) cm

B.
Keliling = 3x + 5
17 = 3x + 5
3x = 17 - 5
3x = 12
x = 12/3
x = 4 cm

Maka sisi sisi segitiga adalah
(x + 2) cm = (4 + 2) cm = 6 cm
(x + 1) cm = (4 + 1) cm = 5 cm
(x + 2) cm = (4 + 2) cm = 6 cm