14x + 3y = 14,80
6x + 7y = 13,20
14x = 14,80 - 3y
x = 14,80 - 3y / 14
6 ( 14,80 - 3y / 14 ) + 7y = 13,20
-18y/14 + 7 y = 13,20 - 6,34
-18y/14 + 98y/14 = 6,86
80y/14 = 6,86
y =6,86/ 80/14 = 6,86 x 14/80 = 96,04/80 = 1,20
14x + 3 ( 1,20 ) = 14,80
14x + 3,60 = 14,80
14x = 14,80 - 3,60
14X = 11,20
x = 11,20/14
= 0,80
une tulipe coute 0,80 € et une rose coute 1,20 €
