神马作文网
40-2.8-x=0.
3/2x-2.8+x=0.
56-x =x- (40-x)
2.2x-x=0.
X/(x-30)=(x+40)/X解方程,
(X+X*20%)-[(1200-X)-(1200-X)*20%]=40%
X+X*20%-(1200-X)-(1200-X)*20%=40%
f(x)=x,x≥0.f(x)=x+a,x
已知两个函数f(x)=｛x²,x≥0,-x,x＜0,g(x)=｛x分之1,x＞0,-x,x≤0.
13.2x+9x=33.3 8x-3X=105 5.4x+x=12.8 x-0.
若x+x^2+x^3+x^4=0.求x^5+x^6+…+x^2004的值
（X+X)+(X-X)+(X*X)+(X/X)=100