用加减消元法(1)2x-y=8 2x+5y=-4 (2)2x+5y=17 2x-3y=1 (3)x-y=5 2x+3y-
用加减消元法(1)2x-y=8 2x+5y=-4 (2)2x+5y=17 2x-3y=1 (3)x-y=5 2x+3y-
分式的加减:[(x/y-y/x)除以(x+y)+x(1/y-1/x)]除以1+x/y,其中x=5,y=2
x+y/2+x-y/3=6,4(x+y)-5(x-y)=2用加减消元法解方程组
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
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
用加减消元法:解方程组:(1)x+y=4 2x−y=5 (2)3x+2y=7x+2y=5(3)2x+y=-2
4(x+2y)=12,3x=5+2y(加减消元法)
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5