-5(x-2y+1)-(1-3x+4y)
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
(x+2)(x+3) (x-4)(x+1) (y+4)(y-2) (y-5)(y-3)
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
去括号并合并同类项(1)3x-2(x+7)+2(2x+5) (2)(4x-3y)-[-(3y-x)+(x-y)]-5x
化简1) (-2x^ y^)(3x^ y^)(-4x^ y^)2) (6√x)\(3√x√x^5)3)已知函数f(x)的
(1)﹛2x-y=5 (2) 4x-y=1 (3)5x+y=2 7x-3y=20 y=2x+3 x-3y=4 (4)3x
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
(x/x+y +2y/x+y)乘以xy/ x+2y除以(1/x+1/y)(2)(3x^2/4y)^2乘以2y/3x+ x
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
1) (2x+5y)(2x-5y)(-4x^2-25y^2) 2) [(x+y)(x-y)-(x-y)^2+2y(x-y