{5（x-3y）-6=2x+1 3（x+6y）+4=9y+19

｛4/(x+y)+6/(x-y)=3 ｛9/(x-y)-1/(x+y)=1 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 (1){x+2y=0,3x+4y=6(2){5x+6y=16,7x-9y=5（3）{9x-11y+1=0,4x-5y-3 (1)已知x+y=6,x²-y²=5,求x-y的值（2）若x+y=3,x²+y² x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9 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4x^2+y^2-4x-6y+10=0,求(2\3x根号9x+y^2根号x/y^3)-(x^2根号（1\x）-5x根 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 1.（（y+2x)(-2x+y)+4(x+2y)^2)/3y 2.（2(x-y)^3-8(x-y）^2(x+y)+6y( 3x+2y/4=2x+y/5=x-y+1/6