一元一次式的化簡及運算

分數一元一次式化簡的應用：

(1)
(1/2)(3x - 4)
= (3x/2) - 4

(2)
-(2/3)(6x - 3)
= -4x + 2

(3)
(1/2)(x - 5) + (1/3)(x - 2)
= (x/2) - (5/2) + (x/3) - (2/3)
= (3x/6) - (15/6) + (2x/6) - (4/6)
= (5x/6) - (19/6)

(4)
(1/4)(x - 3) - (1/3)(x - 1)
= (x/4) - (3/4) - (x/3) + (1/3)
= (3x/12) - (9/12) - (4x/12) + (4/12)
= -(x/12) - (5/12)

(5)
(1/5)(3x - 2) + (1/7)(2x - 1)
= (3x/5) - (2/5) + (2x/7) - (1/7)
= (21x/35) - (14/35) + (10x/35) - (5/35)
= (31x/35) - (19/35)

(6)
(1/3)(2x - 4) - (1/2)(3x - 1)
= (2x/3) - (4/3) - (3x/2) + (1/2)
= (4x/6) - (8/6) - (9x/6) + (3/6)
= -(5x/6) - (5/6)


先去小括號，在去中括號: 化簡

2x - [6 - (3x - 4)]
= 2x - [6 - 3x + 4]
= 2x - [10 - 3x]
= 2x - 10 + 3x
= 5x - 10

2(3x - 8) - [9x - (-7x - 2)]
= 6x - 16 - [9x + 7x + 2]
= 6x - 16 - [16x + 2]
= 6x - 16 - 16x - 2
= -10x - 18


一元一次式:

(1)
媽媽共花了
= (x*5 + 2*1) 元
= (5x + 2) 元

(2)
張先生應付
= (800*x + 300) 元
= (800x + 300) 元

美其名留答發問者做，實際是不完整的答案。
這樣的答案，竟得到這麼多票，除了亂投票或分身投票之外，找不出其他原因。

上面那很簡單~作業我上面留給你唷
剩下的我幫你解

1.
2x-[6-(3x-4)]
=2x-(6-3x+4)----------去中括號(變號)
=2x-6+3x-4-----------去小括號(變號)
=5x-10
=5(x-2)----------簡化

2.
2(3x-8)-[9x-(-7x-2)]
=6x-16-(9x+7x+2)----------去中括號(變號)
=6x-16-9x-7x-2-----------去小括號(變號)
=-10x-18
=-2(5x+9)-----------簡化(提負號)

3.列一元一次式:
5x+2

4.列一元一次式:
800x+300(不需化簡)

就是這樣囉~~

2013-12-25 18:13:06 補充：
樓下的大大最後沒有化簡唷˙˙