中一數學文字方程(英文),Help!

你好好人,你是老師來的吧?? ._.

你好~我也是中一生。看看我能不能幫你。

1. Tony and Brian have $370 altogeter. If Tony gives $65 to Brian, the amount of money they have will be same. Find the original amount of money that Tony has.
(Let $x be the original amount of money that Tony has.)

Let $x be the original amount of money that Tony has.
The original amount of money that Brian has=$x-$65x2.
$x+($x-$65x2)=370
$x+($x-$130)=370
2($x)-$130=370
2($x)=370+130
2($x)=500
$x=250
checking:if Tony has $250,Brian has $250-$65x2=$120.
They total money
=$250+$120
=$370
so the answer is correct.

2. The difference between two positive integers is 12. If their sum is 40, find the smaller number.
(Let x be the smaller number.)

Let x be the smaller number.
The larger number=x+12.
x+x+12=40
2x+12=40
2x=40-12
2x=28
x=14
checking:if x=14,the larger number=14+12=26.
Their sum
=14+26
=40
so the answer is correct.

3. The weight of a honeydew melon is one-third of that of a watermelon. If their total weight is 16kg, find the weight of the watermelon.
(Let x kg be the weight of a watermelon.)

Let x kg be the weight of a watermelon.
The weight of a honeydew melon=1x/3
x+1x/3=16
(x+1x/3)x3=16x3
3x+x=48
4x=48
x=12
checking:if the weight of a watermelon=1kg, the weight of a moneydew melon=12xone-third=4
The total weight
=12+4
=16kg
so the answer is correct.


希望可以幫到你~^ ^

2013-10-15 22:37:31 補充：
中文小補充：
1.The original amount of money that Brian has=$x-$65x2.

Q：為什麼Brian的錢是Tony的錢減$65x2？？？？
A：舉個例子：我有$3，我給你$1之後我跟你的錢就一樣了
你會發現我的錢比你多$2，而不是$1，所以我的錢減去$1x2就是你的錢了。
而透入到Brian和Tony裏面去：
Tony給Brian$65之後兩個人的錢就一樣了，再根據上面的例子計算。

明白嗎？

3.(x+1x/3)x3=16x3

Q：這裡為什麼要乘以3呢？
A：因為這樣可以把比較複雜的分數變成比較簡單的整數來計算。

2013-10-20 21:08:31 補充：
大家好~
本來我是想用自己的身份來回答的
但是...
不夠年齡
所以一直在用我媽的
請多多指教！^ ^

(◕‿◕✿)　顧老師，歡迎來臨這邊參與發表～

一般中二的同學才會學習 simultaneous equations，他們於中一的時候主要重溫小學的內容，或配以英語學習，加上少量新的知識，例如 directed numbers。

2013-10-16 00:45:52 補充：
ann 你做得好好！

讓我刪除答案再贊助一下大家！

☆ヾ(◕‿◕)ノ

2013-10-16 00:46:50 補充：
1. 東尼和拜仁共有三百七十元。如果東尾把六十五元給拜仁，那麼他們二人各自的金錢則會相等。求東尼原本有多少元。
（設東尼原本有ｘ元。）
拜仁原有 $(370 - x)。
x - 65 = 370 - x + 65
x - 65 = 435 - x
2x = 500
x = 250
The original amount of money that Tony has is $250.

2013-10-16 00:46:58 補充：
2. The difference between two positive integers is 12. If their sum is 40, find the smaller number.
(Let x be the smaller number.)
兩個正整數的差為１２，如果它們的和是４０，求較小的那個數。
（設ｘ為較小的數。）
大數為 x + 12
x + x + 12 = 40
2x = 28
x = 14
The smaller number is 14.

2013-10-16 00:47:13 補充：
3. 一個蜜瓜的重量是一個西瓜的三分之一。如果兩個瓜共重十六公斤，求西瓜的重量。
（設ｘ公斤為西瓜的重量。）
蜜瓜重 x/3 公斤。
x + x/3 = 16
4x/3 = 16
4x = 48
x = 12
The weight of the watermelon is 12 kg.

2013-10-16 19:38:44 補充：
嗯～
但誰人是誰也不重要～
最緊要發言能夠幫忙～
大家也是盡一分力～

大家要互相尊重～ (=^o^=)

1. Let X be the amount of money Tony has.
Let Y be the amount of money Brian has.
$(X + Y) = $370 ------ (1)
$(X - 65) = $370/2 ----- (2)
From (2), X = $250 --- (3)
Put (3) into (1), $(250 + Y) = $370
Y = $120

2. Let X be the smaller number
Let Y be the larger number
Y - X = 12
Y = 12 + X ------- (1)
Y + X = 40 ------- (2)
Put (1) into (2), 12 + X + X = 40
X = 14 ----- (3)

3. Let X be the weight of the watermelon
1/3X + X = 16Kg
4/3X = 16 Kg
X = 16 x 3/4 Kg
X = 12 Kg