bonjour
a) AD = 6 - x
b) Périmètre ABCD = 2 ( 3 + 6 - x ) = 6 + 12 - 2 x = - 2 x + 18
c) Périmètre DEFG = 2 ( x + 5 ) = 2 x + 10
d) aire ABCD = 3 ( 6 - x ) = 18 - 3 x
e) aire BEFG = 5 x
f ) Périmètre total = - 2 x + 18 + 2 x + 10 = 28
g) aire totale = 5 x + 18 - 3 x = 2 x + 18
a) - 2 x + 18 = 2 x + 10
-2 x - 2 x = 10 - 18
- 4 x = - 8
x = 2
b ) 5 x = 18 - 3 x
5 x + 3 x = 18
8 x = 18
x = 2.25
