(x+12)×4/5=42-x
1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550
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+9x=6x*2+12 x+9-x/3=4
x=x/6+x/12+x/7+5+x/2+4=?
x^3×x^5×x+(x^3)^12+4(x^6)^2=?
1/6x+1/12x+1/7x+5+1/2x+4=x
(x+12)(x-2)+(x+7)(x+8)-(x+5)(x-10),其中x=2
2x+3x+4x+5x+x+6x+7x=100
13x+42-5x=104-12x-22
4x+5x+14=42-2(x+3)
x-4/x-5 - x-5/x-6=x-7/x-8 - x-8/x-9求x=?