4(3y+2)-3(2+y)=3+8y .5(x+ 9-3(9+x)=2 .3(x+(1-2x))=6.急
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
1.((y+2x)(-2x+y)+4(x+2y)^2)/3y 2.(2(x-y)^3-8(x-y)^2(x+y)+6y(
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
2(x-y)+3(x+y)2-5(x-y)-8(x+y)2-(x-y)
9y=3x-(x-1),4(x+y)-(2x+4)=8y
(1){x+2y=0,3x+4y=6(2){5x+6y=16,7x-9y=5(3){9x-11y+1=0,4x-5y-3
计算:(2/3x根号下9x+6x根号下y/x)+(y根号下x/y-x的平方根号下1/x)=
先化简再求值:(x-2y)²-(x+2y)(x-2y)-(x-3y)(x-y).其中x²+9y
化简:(x+y)+(2x+y/1*2)+(3x+y/2*3)+...+(9x+y/8*9)
化简求值8x的平方-5x(4y-x)+4x ×(-4x+5/2y)x=1 y=3