初一数学题

Question

Dua gandaan sepunya yang berturutan bagi nombor x dan (y +5) ialah 30 dan 6y. Apakah nilai GSTK bagi dua nombor tersebut jika beza antara x dan y  ialah 7.

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这是我的答案，不懂对不对。

30×2=6y

      60=6y

      10=y

   y - x = 7

  10-x = 7

       -x  = 7-10

       -x = -3

        x = 3

x=3

y=10

Maka, GSTK/LCM bagi (x=3) dan ((y=10)+5) ialah 15.

谢谢大家的回答。

Comments

哈哈哈哈哈，Travel 抄的被发现了

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这是我练习簿的问题，我不懂做得对不对，所以我才来问。

Answer 1

The two consecutive common multiples of the numbers x and (y + 5) are 30 and 6y. What is the LCM of the two numbers if the difference between x and y is 7.

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6y = 30 x 2    ...    ①

y - x = 7    ...    ②

From ①,

6y = 30 x 2

6y = 60

y = 10   ...    ③

Substitute ③ into ②,

10 - x = 7

-x = 7 - 10

-x = -3

x = 3

The LCM of x and y + 5

= 3 x 5

= 15

   3 |3 , 15 

   5 |1 , 5   

       1, 1    

Comments

Please explain how to do. Thank you for your answer and explaination.

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Thank you very much. You really help me a lots.

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I don’t know whether my answer is correct or not. Please refer to the sample answer. It is better to ask help from your teacher or friends.

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I see the answer is 15 but I don't know the method to solve this promblem. Lastly, thank you for your reply.

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You could refer to my new edit. You can use either substitution method or elimination method to solve this problem.

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Thank you very much. You actually help me a lots.