5x-3*(28-x)=12+2x
x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x
1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550
x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少?
x=4x=254 5x-x=180 3x+x=16 4x-2x=28 15x-11x=12.8 (12+12*1.5)x
(x+12)(x-2)+(x+7)(x+8)-(x+5)(x-10),其中x=2
解方程x/(x-2)=2x/(x-3)+(1-x)/(x-5x+6)
2x+3x+4x+5x+x+6x+7x=100
x(x^2-1)+2x^2 *(x+1)-3x*(2x-5)=x(3x^2-4x)-28
5x+9x=6x*2+12 x+9-x/3=4
x^3×x^5×x+(x^3)^12+4(x^6)^2=?
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!)+.
5[x^2-x]=3[x^2+x]