3/5*(40-x)=30-x
用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+.
x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x
x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少?
5x+2=-8 x=30 3x=5x-14 x
2x+3x+4x+5x+x+6x+7x=100
解方程x/(x-2)=2x/(x-3)+(1-x)/(x-5x+6)
5/8X-30+3/10X+84=X
已知3x*x-x=1,求6x*x*x+7x*x-5x+2000
3x+5x=?x等于
5X+6(X+10)+10(X+30)+6(X+70)+3(X+150)=2730,X等于多少
3x+5(30-x)=126
(5x-30):3x=2: