y=-x²-6x+2 x∈〖-2,4〗求最值

{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 已知x²+y²+13-4x+6y=0,求（2x-y)²-2(2x-y)(x+2y)+(x+ 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 求下列函数的值域 (1) y=x²-2x,x∈{0,1,2,3} (2)y=x²-4x+6,x∈[] 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y y=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10)的导数在x=1 (2x-y)²-4(x-y)(x+2y) 化简：（2x-y)²-4(x-y)(x+y)