X*2.43%*2*(1-20%)=

1)x-10=4(x-28)x-10=4x-1123x=102x=342)3(x-28)=x+56+283x-3*28=x+2*28+282x=6*28x=3*28x=843)2(1.5x-30-20

1、56-8X=11+X8X+X=56-119X=45X=52、3X-2=X+1+6X3X-2=7X+17X-3X=-2-14X=-3X=-3/43、7+X=2X+20-14X7+X=20-12XX+

(1/x^2+3x+2)+(1/x^2+5x+6)+(1/x^2+7x+12)+(1/x^2+9x+20)=1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)+1/(x+4)

(X-X*20%-18)-（X-X*20%-18）*10%=X*1/2-3则（X*80%-18）*90%=X*1/2-372%*X-16.2=X*1/2-322%*X=13.2X=60

化简得2/x^2+6x=0,即（1+3x^3)/x^2=0,所以x=-（1/3)^(1/3)

x+3/20x=4623x/20=46x=46x20/23=40,x-1/5x=404x/5=40x=200/4=50,x-1/2x=3/4x/2=3/4x=3/2,x-0.2x=180.8x=18x

1/x(x+1)+1/x(x+1)(x+2)+1/x(x+2)(x+3)+.+1/x(x+2007)(x+2008)=（1-1/2）+（1/2-1/3）+（1/3-1/4）+……+（1/2007-1/

1/4X=13X=5210/3X=20/21X=2/70.72X=12.96X=18

x【x+1】的平方-x【x的平方-3】-2【x+1】【x-1】=20x³+2x²+x-x³+3x-2x²+2=204x+2=204x=18x=4.5

60X+15X+10X+6X=12091X=120X=120/91

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

1/√x(√x+2)=1/√x-1/(√x+2)=(√x+2-√x)/√x(√x+2)所以,1/√x(√x+2)+1/(√x+2)(√x+4)+1/(√x+4)(√x+6)+.+1/(√x+18)(√

原式=1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)+1/(x+4)(x+5)=1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+1/(x+3)-1/(x+

12481632

1/(x^2+3x+2)+1/(x^2+5x+6)+1/(x^2+7x+12)+1/(x^2+9x+20)＝1/﹙x＋1﹚﹙x＋2﹚＋1/﹙x＋2﹚﹙x＋3﹚＋1/﹙x＋3﹚﹙x＋4﹚＋1/﹙x＋4﹚

六道因式分解的题.!10-离问题结束还有14天23小时(x+y)^4+(x+y)^2-20=[(X+Y)方+5][(X+Y)方-4]=(X方+Y方+2XY+5)(X方+Y方+2XY-4)(x^2+7x

x-(1/5+1/5)x-39=39x-2/5x=39+393/5x=78x=78÷3/5x=130x-1/4x-2/5x=112(1-1/4-2/5)x=1127/20x=112x=112÷7/20

（1-1/2）X+(1/2-1/3)X+(1/3-1/4)X+(1/4-1/5)X+(1/5-1/6)X+(1/6-1/7)X=1(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-

等于(x-1)(x-2)(x-3)(x-4)...(x-50)的导数

1/x^2-3x+2-1/x^2-5x+6-1/x^2-7x+12-1/x^2-9x+20=1/(x-1)(x-2)-1/(x-2)(x-3)-1/(x-3)(x-4)-1/(x-4)(x-5)=1/