2x-3y-2=0 5x+3y=18 2x-3y=7 (2x-3y+5)/7+2y=9 2x-3y=3 6x+5y=35
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2x-3y-2=0 5x+3y=18 2x-3y=7 (2x-3y+5)/7+2y=9 2x-3y=3 6x+5y=35 解方程组,快
{2x-3y-2=0
{5x+3y=18 ,
解得{x=20/7,
{y=26/21.
2.{2x-3y=7 ,(1)
{(2x-3y+5)/7+2y=9(2)
把(1)代入(2),12/7+2y=9,
y=51/14,
代入(1),2x-153/14=7,
x=251/28.
3.{ 2x-3y=3 (1)
{6x+5y=35 ,(2)
(2)-(1)*3,14y=26,y=13/7,
代入(1),2x-39/7=3,
x=30/7.
{5x+3y=18 ,
解得{x=20/7,
{y=26/21.
2.{2x-3y=7 ,(1)
{(2x-3y+5)/7+2y=9(2)
把(1)代入(2),12/7+2y=9,
y=51/14,
代入(1),2x-153/14=7,
x=251/28.
3.{ 2x-3y=3 (1)
{6x+5y=35 ,(2)
(2)-(1)*3,14y=26,y=13/7,
代入(1),2x-39/7=3,
x=30/7.
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
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
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
{2x+y/3-2y=0 2(2x+y)-5=7y
y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
解二元一次方程组:{5(x+y)+3(x-y)=2{7(x+y)-3(x-y)=-6