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Ecrits les aires en fonction de x et A(Bleu)=(3/4)A(ABCD):
[tex]A1=A(ABCD) \\A1=6^{2} = 36 \\ \\A2=A(Jaune) \\A2=4\times\frac{x^{2}}{2}=\frac{4x^{2}}{2}=2x^{2} \\ \\A3=A(Bleu) \\A3=A1 - A2 \\A3=-2x^{2}+36 \\ \\A3=\frac{3}{4}A1 \\-2x^{2}+36=\frac{3}{4}36 \\-2x^{2}+36=27 \\-2x^{2}+9=0 \\(3-\sqrt{2}x)(3+\sqrt{2}x)=0 \\<=>\left \{ {{3-\sqrt{2}x=0} \atop {3+\sqrt{2}x=0}} \right. \\\left \{{{-\sqrt{2}x=-3} \atop {\sqrt{2}x=-3}} \right. \\\left \{{{\sqrt{2}x=3} \atop {\sqrt{2}x=-3}} \right. \\\left \{{{x=\frac{3}{\sqrt{2}} \atop {x=\frac{-3}{\sqrt{2}}}} \right.[/tex]
[tex]\\\\\\0<x\leq 3\\ x=\frac{3}{\sqrt{2}}[/tex]
