(1)x-3y=10 ① ⑵ 5x=2y ① ⑶ 2(x-1)<x+1 x+6y=1 ② 23x+2y=5b ② x+2
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)=4 {x+y/2 + x-y/6=1
①{2X-5y=21,②{2x+y=6,③{x-3y=1,④{y=-2x=3 {y=-x.{y=1/2x+1.{5x-9
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
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
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
y=(x^2+x)/(x+1)
① X+Y=3 Y=2X-3 ② x+2y=9 y-3x=1 ③3/x+1=y 2(x+1)=6 ④ y-x=3 7x-
(2x+y-1)(2x-y+1)-(3x+y)(3x-y),其中x=5分之1,
y=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10)的导数在x=1