4x^2+3y^2=3x∴4x^2+4y^2=3x+y^2∴4（x^2+y^2）=3x+y^2∵y^2=x-4/3x^2∴4(-1/3x^2+x)=3x+y^2∴只要-1/3x^2+x有最大值,则3x+y^2有最大值-1/3x^2+x的最大值是当x取自变量最大值时∵0≤x≤3/4∴x=3/4∴3x+y^2最大值为9/...