2x+3y = 12
x*y = -2
x = -2/y y ≠ 0
2(-2/y) +3y = 12
-4/y +3y = 12
-4/y +3y^2/y = 12
3y^2 - 4)/y = 12 soit l'équation du second degré : 3y^2 -12y -4 = 0
Δ = 12^2 + 4x3x4 = 192
y1 = 12 +√192/6 = 12+8√3/6 = 6+2/3√3
y2 = 6-2/3√3
d'où x1 = -2/6+2/3√3 x2 = -2/6-2/3√3
Vérification
x*y = -2 ; -2/6+2/3√3) * (6+2/3√3 = -2
il faut la vérifier
2x + 3y = 12 ; 2(-2/6+2/3√3) + 3(6+2/3√3) = 12
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Verified answer
2x+3y = 12
x*y = -2
x = -2/y y ≠ 0
2(-2/y) +3y = 12
-4/y +3y = 12
-4/y +3y^2/y = 12
3y^2 - 4)/y = 12 soit l'équation du second degré : 3y^2 -12y -4 = 0
Δ = 12^2 + 4x3x4 = 192
y1 = 12 +√192/6 = 12+8√3/6 = 6+2/3√3
y2 = 6-2/3√3
d'où x1 = -2/6+2/3√3 x2 = -2/6-2/3√3
Vérification
x*y = -2 ; -2/6+2/3√3) * (6+2/3√3 = -2
il faut la vérifier
2x + 3y = 12 ; 2(-2/6+2/3√3) + 3(6+2/3√3) = 12