bonsoir résoudre 1 4x-2y=12 7x+4y=16 2 8x+3y=32 5x+4y=13 merci de vos reponse

Bonsoir;

4x-2y=12
7x+4y=16

8x - 4y = 24
7x + 4y = 16
x = 40

4x - 2y = 12
4 * 40 - 2y = 12
160 - 2y = 12
- 2y = 12 - 160
- 2y = - 148
y = 148/2
y = 74

Les solutions sont : (40 ; 74)

8x+3y=32
5x+4y=13

- 32x - 12y = - 128
15x + 12y = 39
- 17x = - 89
x = 89/17

5x + 4y = 13
5 (89/17) + 4y = 13
445/17 + 4y = 13
4y = 13 - 445/17
4y = 221/17 - 445/17
4y = - 224/17
68/17y = - 224/17
68y = - 224/17
y = - 224/68
y = - 56/17

Les solutions sont : (89/17 ; - 56/17)