Réponse :
Bonsoir
Explications étape par étape :
1) 3x + 4y = 1
x - 2y = 2
= 3x + 4y = 1
x = 2 + 2y
= 3 (2 + 2y) + 4y = 1
y = -1/2
= 2 + 2 x (-1/2)
x = 1
S = (1; -1/2)
2) 5x - 2y = 4
-3x + 4y = 6
= x=4/5 + 2/5 y
-3x + 4y = 6
= -3(4/5 + 2/5 y) + 4y = 6
y = 3
= x = 4/5 + 2/5 x 3
= 5 x 2 – 2 x 3 = 4
-3 x 2 + 4 x 3 = 6
S= (2; 3)
3) C'est flou désolé
4) x+y=3√2
xy = 4
= 3√2-y
xy = 4
= y = 2√2
y = √2
= x = 2√2
x = √2
S(√2; 2√2)
5) x + y = 2
x² + y² = 10
= x = 2 - y
x² + y² = 10
= y = -1
y = 3
= x = 2 - (- 1)
x = 2 - 3
S=(-1; 3)
6) x² - xy + y² = 13
x + y = -2
= x² - xy + y² = 13
x= -2 - y
= x = 1
x = 3
= 13 = 13
-2 = -2
= 13 13
-2 = -2
S=(-3; 1)
Voilà
