10x+(50-x)/2*(5+2)=240 怎么解

(x+12)(x-2)+(x+7)(x+8)-(x+5)(x-10),其中x=2 10x+2x*[(50-x)/2]+5x[(50-x)/2]=240 填空:(x+5)(x+?)=x^2+7x+10 1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10+x^11+x^12=97.8x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10+x^11+x^12=97.8 好多年没有用过过数学公式了 想不起来怎么算了 想知道 X值是多少 已知x=2π+1求 |x-1|+|x-2|+|x-3|+|x-4|+|x-5|+|x-6|+|x-7|+|x-8|+|x-9|+|x-10| 已知x=2π+1.求(X-1)+(X-2)+(X-3)+(X-4)+(X-5)+(X-6)+(X-7)+(X-8)+(X-9)+(X-10) =(x^2-5x)^2+10(x^2-5x)+24 =x^4-10x^3+25x^2+10x^2-50x+24 这是怎么转化的(X-1)(X-2)(X-3)(X-4) =(X-1)(X-4) (X-2)(X-3)=（x^2-5x+4)(x^2-5x+6)=(x^2-5x)^2+10(x^2-5x)+24=x^4-10x^3+25x^2+10x^2-50x+24=x^4-10x^3+35x^2-50x+24 1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10+x^11=17.7这个方程怎么样求解? =（x^2-5x+4)(x^2-5x+6) =(x^2-5x)^2+10(x^2-5x)+24 是怎么转化的(X-1)(X-2)(X-3)(X-4) =(X-1)(X-4) (X-2)(X-3)=（x^2-5x+4)(x^2-5x+6)=(x^2-5x)^2+10(x^2-5x)+24=x^4-10x^3+25x^2+10x^2-50x+24=x^4-10x^3+35x^2-50x+24不好意思我弄错了，是=（x^2-5 2x+8-10x+50=5x-10 (x+2)(x^2+5x-10)-(x+2)^2(x-1),其中x=1.5 (x+2)(x^2+5x-10)-(x+2)^2(x-1),其中x=1.5, 15X(4X-8)-5X(2X+10)=6X(5X-20) 1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550必须用解方程 xy²/(x²y-y) × x²/(x²+x)=(x²-3x)/(x²-5x) × 2x-10/(x²-6x+9)=化简求植x²-1/(x²-x-2)除以x/2x-4,其中x=1/2[x-x/(x+1)]除以[x/(2x-4)] ,其中x=√2+1 *-----------------------------------------------*| 6 4 X | 8 X X | X X 5 || X X X | X X X | X 7 8 || X X X | X X X | X X X ||---------------+---------------+--------------- || X X X | X X X | 5 1 X || X X X | X 6 X | X X X || 8 X X | 3 5 X | 2 X X || x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? 1x()+2x()+3x()+4x()+5x()+6x()+7x()+8x()加9x()+10x()=1980