y=(3+x)(1-2x)化简成y=a(x-h)²+k的形式

已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 A={(x,y)|y=-x^2+mx-1},B={(x,y)|y=3-x,0A={(x,y)|y=-x^2+mx-1},B={(x,y)|y=3-x,0 集合A={（x,y)|y=-x^2+mx-1},B={(x,y)|y=3-x,0 1、(-y^3)^5/y^3/ y^2+2(-y)^102、(x-y)^7/(y-x)^6+(x+y)^3/(x+y)^23、已知X^a=5,x^b=3,求X^(3a-2b)的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 二元一次方程 ：2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 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 变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y (x-y)^2+(x+y)(x-y) 其中 X =3 Y=-1 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 设集合A={x|x=y^2-2y-8},B={x|y=-x^2+2x+3},C={y|y+1 因式分解 1：（x+y)(x+y)-(x+y)^2=?2：(x+y))^2+mx+my=?3：a(x-a)(x+y)^2-b(x-a)^2(x+y)=? 当A=1,Y=-2时,代数式X-(X+Y)+(X+2Y)-(X+3Y).-(X+99Y)值是( ) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 集合A={y/y=1-x-4/x},B={X/X^2-(3+a)X+3a 集合A={y|y=1-x-(4/x)},B={x|x^2-(3+a)x+3a