8x=7x49

48x54—48x3+48x49=48x（54-3+49）=48x100=4800

49.5x13.5+50.5x13-0.5x49.5=49.5x（13.5-0.5）+50.5x13=49.5x13+50.5x13=(49.5+50.5)x13=100x13=1300如果本题有什么不明白可以追问,如果满意请点击“好评”

有一个式子：1/a(a+1)=1/a-1/a+1应用到这里1/1X2+1/2x3+1/3x4+.1/48x49+1/49x50=(1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/49-1/50)=1-1/2+1/2-1/

x(1+2+...+9)=x(9-8-7-...-1)x=0记得采纳啊

=x^2+10x-24+x^2+15x+56-x^2+5x+50=x^2+30x+82=4+60+82=146其实,不化简,直接代入=14*0+9*10+7*8=0+90+56=146也很简单

首先回答:X7X-X7X=X98设被减数的百位数字是a,个位数字是b,其中(0

(X-4)/(X-5)-(X-5)/(X-6)=(X-7)/(X-8)-(X-8)/(X-9)[(x-4)(x-6)-(x-5)2]/(x-5)(x-6)=[(x-7)(x-9)-(x-8)2]/(x-8)(x-9)(x2-10x+24-x

变形得9X—5=5X—1得4X=4得X=1再答：有不懂的再问再问：对啊……我就是想知道怎么变形……不过你这个比较详细一些……再问：右边是7-2变形，那左边是……再答：就是把未知数X移到一边再问：右边是不是7-2变形呀？那左边是怎么变的？我4

/>因为：x-5/x-6+x-8/x-9=x-7/x-8+x-6/x-7,所以：1+1/(x-6)+1+1/(x-9)=1+1/(x-8)+1+1/(x-7)即：1/(x-6）+1/(x-9)=1/(x-8)+1/(x-7)所以：1/(x-

设a=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)那么y=a*(x-10);那么y^=a^*(x-10)+a*(x-10)^=a^*(x-10)+a那么y^|10=a^*(10-10)+a=9!

(x-10+2)/(x-10)+(x-6+2)/(x-6)=(x-7+2)/(x-7)+(x-9+2)/(x-9)1+2/(x-10)+1+2/(x-6)=1+2/(x-7)+1+2/(x-9)1/(x-10)+1/(x-6)=1/(x-7

解(x-3)(x-7)/(x^2-8x+7)-(x-5)(x-1)/(x^2-8x+7)+(x^2-x)/(x^2-8x+7)=1x^2-10x+21-(x^2-6x+5)+x^2-x=x^2-8x+7整理得3x+9=0x=-3经检验x=-

 再问：额、不懂再答： 再答：后面的看做一个整体再问：好的吧、谢谢大神再答：回来的话，请采纳再问：啊、突然明白了呢。。。

x+x^2+x^3+x^4+x^5+x^6+x^7+x^8=（x+x^2+x^3+x^4）+（x^5+x^6+x^7+x^8）=x（1+x+x^2+x^3）+x^5（1+x+x^2+x^3）=（x+x^5）（1+x+x^2+x^3）=（x+

1+x+x^2+x^3=0x+x^2+x^3+x^4+x^5+x^6+x^7+x^8=(x+x^2+x^3+x^4)+(x^5+x^6+x^7+x^8)=x(1+x+x^2+x^3)+x^5(1+x+x^2+x^3)=0+0=0

[1-1/(x-4)]+[1-1/(x-8)]=[1-1/(x-7)]+[1-1/(x-5)]1/(x-4)+1/(x-8)=1/(x-7)+1/(x-5)(x-4+x-8)/(x-4)(x-8)=(x-7+x-5)/(x-7)(x-5)(

即1/(x-5)+1/(x-9)=1/(x-6)+1/(x-8)(2x-14)[1/(x-5)(x-9)-1/(x-6)(x-8)]=01/(x-5)(x-9)-1/(x-6)(x-8)≠0所以2x-14=0x=7经检验,成立

通分得[（x-8）(x-4)-(x-9)(x-3)]/(x-3)(x-4)=[(x+7)(x+3)-(x+2)(x+8)]/(x+8)(x+3)解得5/(x-3)(x-4)=5/(x+8)(x+3),所以(x-3)(x-4)=(x+8)(x

(x+8)/(x-3)-(x-9)/(x-4)=(x+7)/(x+8)-(x+2)/(x+3)[（x-8）(x-4)-(x-9)(x-3)]/(x-3)(x-4)=[(x+7)(x+3)-(x+2)(x+8)]/(x+8)(x+3)解得5/