2.7÷(1-30%-1 4)x1 4=1.5

[（x+2）/（x*x-2x）-（x-2）/（x*x-4x+4）]/[(x-4)/x]=[（x+2)/x(x-2)-(x-2)/(x-2)²]/[(x-4)/x]=[(x²-4-x

=（x+1）(x-1)(x+1)x-1--------------÷------×-----(x-1)^2(x-1)x+1=x+1---x-1

(x+1-1/1-x)÷(x-x²/x-1)=[(x+1)+1/(x-1)]×[-(x-1)/x(x-1)]=(x²-1+1)/(x-1)×(-1/x)=-x/(x-1)(x-4/

1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550120x=550x=55/12=4.583

计算：（1+1/x）·x²-2x+1/x²-1；=（x+1）/x×(x-1)²/(x²-1)=(x-1)/x;（x²/x-1-2x/1-x）÷x/x-

解题思路：分式的混合运算，按照分式运算法则进行计算。解题过程：

(1)3.5x+x-14=18.44.5x=32.4x=7.2(2)2.7*2-1.5x=05.4=1.5xx=3.6(3)13x-6.8x+x=46.87.2x=46.8x=6.5(4)17.5-0

先化简去掉中括号：(1-x+x-1/x)÷(1-1/x-1)再化简：(1-1/x)÷(-1/x)=(1-1/x)x(-x)=1-x

原式=[x(x-3)/(x-3)²][(x-5)(x-6)/x(x-5)]-1=[x/(x-3)][(x-6)/x]-1=(x-6)/(x-3)-1=(x-6-x+3)/(x-3)=-3/(

x/2+x/6+x/12+x/20+x/30+x/42=136x/42=1x=7/6

解1：原式=x(x-1)/(x+1)*(x+1)/x=x-1解2：原式=(x+3)^2/(x+3)(x-3)*(x-3)/(x+2)=(x+3)/(x-3)*(x-3)/(x+2)=(x+3)/(x+

2x/(x-2)(x+1)÷(1－x/x+1)-x²+2x/x²-4?=2x/(x-2)(x+1)×(x+1)/(1-x)-x(x+2)/(x+2)(x-2)=2x/(x-2)(1

=【3x(x+1)-x(x-1)]/(x+1)(x-1)×(x+1)(x-1)/x=(3x²+3x-x²+x)/x=4

x-30%x=1470%x=14x=20x+25%x=20125%x=20x=16

原式=(x-1)(x^15+x^14+……+1)/(x-1)=(x^16-1)/(x-1)=(x^8+1)(x^4+1)(x²+1)(x+1)(x-1)/(x-1)=(x^8+1)(x^4+

x^3+x-30(分解因式)=(x^3-27)+(x-3)=(x-3)(x^2+3x+9)+(x-3)=(x-3)(x^2+3x+9+1)=(x-3)(x^2+3x+10);x^12-y^12;=(x

x²－3x＝2x＋14x²－5x＝14∴﹙4x³－6x²＋2x﹚/2x－﹙x＋1﹚²＋1＝2x²－3x＋1－x²－2x－1＋1＝x

x(2-1/x)+x/(x^2-2x)÷(3-x)/(x^2-4)=x((2x-1)/x)+x/(x^2-2x)x(x^2-4)/(3-x)=(2x-1)+(x+2)/(3-x)=(7x-3-2x^2

(1)2+x/10=3/10x+1x/5=1x=5(2)3/25x+21/5-7/50x=41/5=1/50xx=10(3)未知数不见了(4)1.5x+165-1.1x=1700.4x=5x=12.5

你的括号丢得太多了,我猜猜猜1、实在猜不出来,哪里该有括号2、2X/(2X-1)+X/(X-2)=2[2X(X-2)+X(2X-1)]/(2X-1)(X-2)=22X^2-4X+2X^2-X=4X^2