Bonsoir
soit x le coca et y le jus d'orange
tu as
12x + 8y =25
9x +5y = 18.10
12x +40 y = 125
-72x -40 y = - 144.80
-60 x = -19.80
x = 0.33
un coca vaut donc 0.33 euros
12 x0.33 + 8y = 25
3.96 +8y = 25
8y = 25 -3.96
8y = 21.04
y = 2.63
3 cocas et 3 oranges valent 3 x 0.33 + 3 x 2.63 = 5.88 euros
