Làm thế nào vậy ???

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địt lồn mẹ mày bú buồi đầu buồi liếm lông chim

bạn học lớp 6b k

T bắt quả tang con quỳnh lên mạng hỏi bài nhé

em ko làm được khó vãi làm được mỗi bài 1 với bài 3 còn bài 2 làm ko ra

Gọi số đó là ab (a; b là chữ số ; a khác 0)

theo bài cho ta có: 

ab = 3ab

=> 10a + b = 3ab 

=> 10a - 3ab + b = 0 

=> a(10 - 3b) - \(\frac{1}{3}\)(10 - 3b) + \(\frac{10}{3}\)=0 

=> 3a(10 - 3b) - (10 - 3b) + 10 = 0

=> (3a - 1)(10 - 3b) + 10 = 0

=> (3a - 1)(3b - 10) = 10 = 1.10 = 2.5 = 5.2 = 10.1

+) Nếu 3a - 1 = 1 thì a = 2/3(Loại vì a là chữ số)

+) Nếu 3a - 1 = 2 thì a = 1 và 3b - 10  = 5 => b = 5 (Chọn)

+) Nếu 3a - 1 = 5 thì a = 2 và  3b - 10 = 2 => b = 4 (Chọn)

+) Nếu 3a - 1 = 10 thì a = 11/3 (loại)

Vậy các số  thỏa mãn yêu cầu là 15; 24

a) 102; 111; 120; 210; 201; 300

b) 4000 3100 3010 3001 2002 2020 2200 2011 2101 2110 1111 1003 1030 1300 1210 1201 1120 1102 1012 1021 v.v..

Nếu thiểu bổ sung hộ mk.

106

115

124

133

142

151

160

6 x 9 = 54 số

111, 120 , 210, 300

111,102, 201 ,120  

MK CHỈ LÀM BÀI ĐẦU CÒN BÀI SAU CẬU GIỰA VÀO NÓ MÀ LÀM NHA .VÌ MK HƠI BẬN :

VÌ SỐ ĐÓ GẤP 3 LẦN TỔNG NÊN :\(ab=3.\left(a+b\right)\)

\(=>10.a+b=3.a+3.b\)

\(=>7.a=2b=>3,5.a=b\)

VỚI \(a=1\)THÌ \(b=3,5\)(loại )

VỚI \(a=2\)THÌ \(b=7\)(CHỌN)\(=>ab=27\)

VỚI \(a=3\)thì \(b\)>=9(loại)

vẬY SỐ CẦN TÌM LÀ :27

            - Gọi số cần tìm là ab (a khác 0 , a,b<10)

              Theo  bài ra ta có:       (a+b) x 3 =ab

                                           a x 3 +b x 3 = ab

                                          a x 3 + b x 3 = a x 10 + b (áp dụng phân tích số)

                                                 b x 3 - b = a x 10 - a x 3

                                              b x ( 3- 1 ) = a x ( 10 - 3) (áp dụng 1 số nhân 1 hiệu )

                                                      b x 2 = a x 7

                                                  Vì b x 2 = a x 7 nên a phải = 2 .

        Với a = 2 thì b = 2 x 7 : 2 = 7

        Ta được số :27 

          Thử lại : 27 : 3 = (2+7)  (Đúng)

          Vậy số cần tìm là 27

           yêu cầu thứ 2 bạn tự làm nhé!

Các số đó là : 123 ; 132 ; 213 ; 231 ; 321; 312.

số 1,2,3 nha