9x+14×(20-x)=220
x-30%x=14x+25%x=20
x-3(20-x)=3x-7(9-x)
1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550
-6x+3=2x+11 x=3/2x+14 3/4x-6=3/2x+3 20-3x=7x+4 5/9x+2=1/3x+4
20+0.8x=x-14 112-4x=2x(80-4x)
(x-22)+(x-24)+(x-27)+(x-20)=x
7x-14=5x+9 3x-12=5x-20 56x=42(x+2)用方程解答(五年级的)
解方程:20%X+30%X=2.5; X-14
0.3X+0.6*(20-X)=9,求X
x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少?
如果3x*x-x=1那么9x*x*x*x+12x*x*x-3x*x-7x+2001等于多少