1.25x(4-0.8)

x-4x=102x-0.8x=22x-4x=102x-0.8x=22x-4x=102-3x=102x=-34x-0.8x=220.2x=22x=110第一题x=-34第二题x=110等等

20+0.8x=x-14112-4x=2x(80-4x)20+0.8x=x-14x-0.8x=20+140.2x=34x=170112-4x=2x(80-4x)112-4x=160-8x8x-4x=160-1124x=48x=12

4x+x×1.25x=360(解方程)1.25x^2+4x-360=05x^2+16x-1440=0x1,2=[-16土√(256+20×1440)]/10=[-16土16√(113.5)]/10=1.6[-1土√113.5]x1=1.6(

3/(7X)+4/7(1.25X)=1/X3/(7X)+4/7(1.25X)=1/X-8两边同乘以7*1.25x,3*1.25+4=7*1.25-8*7*1.25x70x=(7-3)*1.25-4x=1/70

4*1.25x+4x=360是不是求X5x+4x=3609x=360x=40

(x+1.25x)乘4=360,2.25x×4=3602.25x=360÷42.25x=90x=90÷2.25x=40

4（x+1.25x）=360x十1.25x=902.25x=90x=404x+5x=3609x=360x=360÷9x=40=4（2.25X）=3604（x+1.25x）=360x+1.25x=902.26x=90x=40x+1.25x=5

x-4=0.8x+4x-4=0.8x+4x-0.8x=4+40.2x=8x=40

4X-0.8X=6.4X—0.8x=6.43.2X=6.4X=2就直接做嘛，4X-0.8X=3.2X，3.2X=6.4,所以X=2！3.2X=6.4X=6.4/3.2X=2先4X-0.8X=3.2X,再6.4/3.2=2，所以X=2

4x-0.8x=6.为什么4x-0.8x=6.4如果你不懂可以看成(4-0.8)x=6.43.2x=6.4x=2

0.8^x=-4,x=?无解吧,0.8^x>0的

解方程：x-4分之一x=8分之3,x等于过程：x-0.8x=22x等于：x-4分之一x=8分之33x/4=3/8两边乘以86x=3x=3/6=0.5x-0.8x＝220.2x＝22x＝22/0.2x＝110

x-4/1x=8/3x-0.8x=22.3/2x+2/1x=42(1)(1—4/1)x=8/34/3x=8/3X=3/8除4/3(2)(1-0.8)x=220.2x=22x=110(3)7/2x=42x=12

(1)1.2:x=0.5(2)x:1.25=1/4(3)x:1/2=0.8解1.2：x=0.51.2：x=1:2x=2×1.2=2.4x：1.25=1/4=1:4∴4x=1.25×1即4x=1.25∴x=0.3125x：1/2=0.8x:1

4x-1.55x-0.81.2-x-------＝----0.50.20.4x-1.55x-0.81.2-x-------＝----0.50.20.18x-3-(25x-4)=12-10x;-17x+1=12-10x;11=7x;x=11/

4x一5/0.5—5x-0.8/0.2=1.2-x/0.1x=4.7

4x(0.8+x)=7.2,0.75x+6=2x4x(0.8+x)=7.23.2+4x=7.24x=7.2-3.24x=4x=10.75x+6=2x2x+0.75x=62.75x=6x=24／11

2.5x8—2.4x=10.40.8x（x+0.8）=0.83x（x+2）=4x（x+1）解方2.5x8—2.4x=10.40.8x（x+0.8）=0.83x（x+2）=4x（x+1）解方成要过成全能答几个算几个,全答采纳.速度 

(x/x-2-x/x+2)/4x/x-2(x/x-2-x/x+2)÷4x/x-2=[x(x+2)-x(x-2)]/(x+2)(x-2)×(x-2)/4x=4x/(x+2)(x-2)×(x-2)/4x=1/(x+2)

x*x*x-4x*x+12x分解因式原式=x(x²-4x+12)=x[（x-2）²+8]希望可以帮到你.=x(x^2-4x+12)=x(x+2)(x-4)