0.6:0.2=3/4:x

0.13x-0.13=0.07x+0.070.13x-0.07x=0.13+0.070.06x=0.2x=20/6(二十分之六）都乘以6030x-10x+7.5x-6x=43/6021.5x=43/6

是这样的：x^5+x^4=x^3(x^2+x)=(x^2+x)[(x^3-1)+1]=(x^2+x)(x^3-1)+x^2+x=[x(x+1)(x-1)](x^2+x+1)+x^2+x=(x^3-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

x(1+2+...+9)=x(9-8-7-...-1)x=0记得采纳啊

2x+3x+4x+5x+x+6x+7x=10028x=100x=100/28x=25/7

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

10（3x-1)/3=10(4-x)/6+10(3x+5)/2（3x-1)/3=(4-x)/6+(3x+5)/22（3x-1)=4-x+3(3x+5)6x-2=4-x+9x+156x+x-9x=4+1

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

0.6（4-x）-5(0.2x+0.34)+5.3=02.4-0.6x-x-1.7+5.3=01.6x=6x=3.752x-3/2+x+6/5=7x-3/107x-2x-x=6/5-3/2+3/104

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+

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

设x1=4-√3,x2=4+√3,是方程X^2-8X+13=0的两根所以X1^2-8X1+15=2X^4-6X^3-2X^2+18X+23=(X+1)^2*(X^2-8X+13)+10=10所以原式=

5x+3=x-44x=-7x=-7/4----------------4y+11=22,4y=11y=11/4-------------------11x+68-2x=100-9x,9x+68=100

3x+0.5x=4.23.5x=4.2x=4.2÷3.5x=1.24x-2.16=1.24x=3.36x=0.84x-0.2x=160.8x=16x=202x-4x乘以2.5=3.62x-10=3.6

1/2x^2-1/4x+0.2x^3+0.25x-0.5x^2-1/5x^3+0.5x-1=(1/2x^2-0.5x^2)+(0.25x-1/4x)+(0.2x^3-1/5x^3)+0.5x-1=0.

2x*4x-3x=8x平方-3x

x=2*[1.25(x-10)-10]x=2*[1.25x-22.5]x=2.5x-451.5x=45x=306.7-0.8x=3(1.7-0.2x)6.7-0.8x=5.1-0.6x1.6=0.2x

=x^2002(x^4+x^3+x^2+x+1)=0提取公因式就行了

(1)3x(x+0.2)=4x(x-1.1)3x+0.6=4x-4.44x-3x=0.6+4.4x=5(2)乘以0.8得4(1-x)=3x4-4x=3x4=7xx=4/7（7分之4）（3）1.1x1.