y=-4x^2+2x-5,x∈[0,+∞)的单调区间

x*x+2x+y*y-4y+5=0 x= y= 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? x*x+y*y-2x+4y+5=0求x, .先化简再求值：（2x+y）（2x+y)-(2x-y)平方其中X,Y满足X平方+Y平方-2X+4Y+5=0 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 y=-4x^2+2x-5,x∈[0,+∞)的单调区间 y=-4x^2+2x-5,x∈[0,+∞)的单调区间? {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 已知7x+5y/2y-x=3/2,且x≠0,求X/x-4y 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 x*x+4y*y+2x*x-4y+2=0求根号下5x*x+16y*y的值快啊 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 先化简,再求值 [2/3x - 2/x+y（x+y/3x -x-y）]*x/x-y,其中5x+3y=0