化简y=|6-x|-|2x+1|+|x+5|.然后求y的最值

2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 化简 3x(x^2-x-1)-(x+1)(3x^-x) X^3(x-y)+x(y-x) 求值域 1,y=(x+2)/(x*x+3x+6) 2,y=3x/(x*x+4) 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 化简：y=|x-1|+|x+2| 1.(x-2y)(x+2y)-(x平方+y)(x平方-y) 2.(2x-y)(y+2x)-(2y+x)(2y-x)3.已知：x+y=6,x平方-y平方=48,求x,y的值4.x平方-2x分之x+2 -- x平方-4x+4分之x-1 化简,求值:[(x-2y)^2+(x-2y)(x+2y)-2x(2x-y)]/2x,其中x=5.y=-6 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 (x-2y)(x+y)-2x(-2x-3y)+6x(-x-y),其中x=-1,y=2 (x-2y)(x+y)-2x(-2x-3y)+6x(-x-y),其中x=-1,y=2要讲解和答题 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 化简 x / y(x+y) - y / x(x+y) = 化简y(x+y)+(x+y)(x-y)-x^2 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 y=(6x^2-4x+1)/x xy²/(x²y-y) × x²/(x²+x)=(x²-3x)/(x²-5x) × 2x-10/(x²-6x+9)=化简求植x²-1/(x²-x-2)除以x/2x-4,其中x=1/2[x-x/(x+1)]除以[x/(2x-4)] ,其中x=√2+1