化简:6+9(x-1)=13+8(y-1)
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
化简(x+y)+(2x+1/2y)+(3x+2/3y)+(4x+3/4y)+...+(9x+8/9y)=?
{2x-5y=21,{2x+y=6 {x-3y=1 {y=-2x+3 y=-x; y=1/2x+1 5x-9y=-13
化简:6+9(x-1)=13+8(y-1)
9y=3x-(x-1),4(x+y)-(2x+4)=8y
x^2+y^2-4x-6y+13=0,求(2/3根号9x+y^2根号x/y^3)-x^2根号1/x-5x根号y/x)的值
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
化简:(x+y)+(2x+y/1*2)+(3x+y/2*3)+...+(9x+y/8*9)
化简(x+y)+(2x+y/1*2)+(3x+y/2*3)+.+(9x+y/8*9)
用代入法 1,x-y=4 4x+2y=-1 2,x-y=13 x=6y-7 3,5x-y=110 9y-x=110
解方程组{4/x+y+6/x-y=3, 9/x-y-1/x+y=1
解方程组:{4/x+y+6/x-y=3 9/x-y-1/x+y=1}