Math 方程

main purpose: to eliminate the denominator and bracket
1) 4x/5 - (-x+5) = -(x-3) - 2(2+2x)/5
= 4x-(-5x+25) = -(5x-15)-2(2+2x)
=4x+5x-25=-5x+15-4-4X
=18x=36
x=2
3) (x+0.75)/0.125-(x-0.25)/0.25 = 15
= 0.25(x+0.75) -0.125(x-0.25)=15
=0.25x+0.1875-0.125x+0.03125 = 15
=0.125x=14.78125
x=118.25

2008-05-16 03:39:31 補充：
4) 9x/5-(3x-2)/10=(2x+1)/5
10(9x)-5(3x-2)=(2x+1)/5
90x-15x+10=(2x+1)/5
5(90x-15x+10)=2x+1
450x-75x+50=2x+1
373x=-49
x=-49/373

2008-05-16 03:51:55 補充：
2) 0.4-0.6(x-3) =1x/3-3(x-7)/5
0.4-0.6x+1.8=5x-9(x-7)
2.2-0.6x=5x-9x+63
3.4x=60.8
x=17.88

2008-05-16 04:10:51 補充：
5) 2x-2(x-2)/3=1/3[x-1/2(3x+1)]
6x-2(x-2)=1/3[x-1/2(3x+1)]
6x-2x+4=1/3[x-1/2(3x+1)]
4x+4=1/3[x-1/2(3x+1)]
12x+12=x-1/2(3x+1)
12x+12=2x-1(3x+1)
12x+12=2x-3x-1
x=-1

2008-05-16 04:35:18 補充：
6) (0.4x+0.9)/0.5-(0.03+0.002x)/0.03-(x-5)/2=0
0.03(0.4x+0.9)-0.5(0.03+0.002x)-(x-5)/2=0
0.012x+0.9-0.015-0.001x-(x-5)/2=0
2(0.012x+0.9-0.015-0.001x)-(x-5)=0
0.024x+1.8-0.03-0.002x-x+5=0
-1.022x=-6.77
x=6.624

Q2: 0.4-0.6(x-3) = 3分之1x -5分之3(x-7 )
.
A2:X=1.3

Q3:125 分之x 0.75 - 0.25分之x-0.25 =15
A3:0.191400625

Q4:4. 5分之9x -10分之3x-2 = 5分之2x 1
A4:6分之1

Q5:2x - 3分之2(x-2) = 3分之1【x-2分之1(3x 1)】
A5:1

Q6:0.5分之0.4x 0.9 -0.03分之0.03 0.002x - 2分之x-5 = 0
A6:2.851