4/3:12/11=x:20/1
1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550
解方程 x+4/11x=75 x-1/4x=120 3x+12x=180 8x-x=175
x-(1/5+1/5)x-39=39 x-1/4x-2/5x=112 x-1/6x-1/3x-12=20
已知X=π/3,试求|X+1|-|X+2|+|X+3|-|X+4|.+|X+11|-|X+12|+|X+13|的值
已知x等于负三分之π,|x+1|-|x+2|+|x+3|-|x-4|+...+|x+11|-|x+12|+|x+13|=
4(x+3)=2x+2 7(x-1)=2x+3 4x+20=6x-30 4x-12=2x 2x-3=x+7 3x-4=2
(X+4)/0.2-(X-3)/0.5=0.2 x-(x-1)/6=3-(x+2)/3 x/12-(2x-1)/20={
-6x+3=2x+11 x=3/2x+14 3/4x-6=3/2x+3 20-3x=7x+4 5/9x+2=1/3x+4
4x-2=3-x -7x+2=2x-4 -x=-0.4x+1 11x+1=5(2x+1) 4x-3(20-x)=3 5(
x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x
x+1/10-x-1/5=1 x/12-2x-1/20=3x+4/8-
若x=π/3,|x+1|+|x+3|+...+|x+13|-|x+2|-|x+4|-...-|x+12|