初學方程,有幾條不太識計,高手來幫幫我!

a)
6[2x-3(x+1)]=2x-106(2x-3x-3)=2x-106(-x-3)=2x-10-6x-18=2x-10-8=8xx=-1

b)
2[x-(2-3x)]=13x+42(x-2+3x)=13x+42(4x-2)=13x+48x-4=13x+4-8=5xx=(-8)/5

c)
2[(3x-4)+2x]=x+102(3x-4+2x)= x+102(5x-4)= x+1010x-8=x+109x=18x=2

d)
5[2(x-3.2)+x] = x-45(2x-6.4+x) = x-45(3x-6.4) = x-415x-32 = x-414x=28x=2

b 個題唔知有冇做錯, 你對吓本書後面個答案

sol
6[2x-3(x+1)]=2x-10
12x-18x-18=2x-10
-8x=8
x=-1
2[(3x-4)+2x]=x+10
6x-8+4x=x+10
x=18
2[x-(2-3x)]=13x+4
2x-4+6x=13x+4
-17x=0
x=0
5[2(x-3.2)+x]=x-4
10(x-3.2)+5x=x-4
10x-32+5x=x-4
14x=28
x=2

2010-11-27 20:46:39 補充：
20pts~

a) 6[2x-3(x+1)]=2x-10
6(2x-3x-3)=2x-10
12x-18x-18=2x-10
12x-18x-2x=-10+18
-8x=8
x=-1

b) 2[x-(2-3x)]=13x+4
2(x-2+3x)=13x+4
2x-4+6x=13x+4
2x+6x-13x=4+4
-5x=8
x=-8/5

c) 2[(3x-4)+2x]=x+10
2(3x-4+2x)=x+10
6x-8+4x=x+10
6x+4x-x=10+8
9x=18
x=2

d) 5[2(x-3.2)+x]=x-4
5(2x-6.4+x)=x-4
10x-32+5x=x-4
10x+5x-x=-4+32
14x=28
x=2