y=(6-5x-x^2)^(-1/2)+(x^2+5x+6)^(3/4)的定义域?

{6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 {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 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 5x+y=6 2x-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 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 初二上学期方程题 4x+y=5 5x+4y=63x-2y=1 2x+3y=13x-2y=7 7x+5y=32x+3y=17 2x-y=-4x+5y=6 2x+y=23x-6y=4 3x+2y=52x+y=73x-4y=53x+y=1x-2y=-1x+y=42x+3y=92x-3y=74x+5y=3x+y=20004x+6y=90003x+5y=113x-2y=42x+3y=215x-2y=5x+y=54x+3y=182x+3y=16x+4y=132x+3y=40x x+y/2+x-y/3=5/6;x=y/6-x-y/3=1/2 已知:2x-y/x+y=1/5,求2x+5y/6x-2y的值 y-x/7-x+y/6=1/2 5(x+y)-2(y-x)=1怎么解答 解方程组6(x-y)-7(x+y)=21 2(x-y)-5(x+y)=-1 3x+2y/4=2x+y/5=x-y+1/6 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 6（x-y)-7(xy)=21,2(x-y)-5(x+y)=-1 6x-2y+[5x-2(y-2x)+y],其中x=-2分之16x-2y+[5x-2(y-2x)+y]y=-6分之1 急 在线等x=-2分之1