Tính B=(5.4^15.9^9-4.3^20.9^9)/(5.2^9.6^19-7.2^29.27^6)

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1. Mình làm theo 2 trường hợp vì đề có vẻ sai nhé !

   1) (có vẻ sai đề)

   `B = (5 . 4^15 . 9^9 – 4 . 3^20 . 9^9)/(5 . 2^9 . 6^19 – 7 . 2^29 . 27^6)`

   `= (5 . (2^2)^15 . (3^2)^9 – 2^2 . 3^20 . (3^2)^9)/(5 . 2^9 . (2 . 3)^19 – 7 . 2^29 . (3^3)^6)`

   `= (5 . 2^30 . 3^18 – 2^2 . 3^20 . 3^18)/(5 . 2^9 . 2^19 . 3^19 – 7 . 2^29 . 3^18)`

   `= (5 . 2^2 . 2^28 . 3^18 – 2^2 . 3^20 . 3^18)/(5 . 2^28 . 3^18 . 3 – 7 . 2^28 . 2 . 3^18)`

   `= (2^2 . 3^18 . (5 . 2^28 – 3^20))/(2^28 . 3^18 . (5 . 3 – 7 . 2))`

   `= (5 . 2^28 – 3^20)/(2^26)`

   `= 20 – (3^10)/(2^26)`

   2) (đúng đề)

   `B = (5 . 4^15 . 9^9 – 4 . 3^20 . 8^9)/(5 . 2^9 . 6^19 – 7 . 2^29 . 27^6)`

   `= (5 . (2^2)^15 . (3^2)^9 – 2^2 . 3^20 . (2^3)^9)/(5 . 2^9 . (2 . 3)^19 – 7 . 2^29 . (3^3)^6)`

   `= (5 . 2^30 . 3^18 – 2^2 . 3^20 . 2^27)/(5 . 2^9 . 2^19 . 3^19 – 7 . 2^29 . 3^18)`

   `= (5 . 2^30 . 3^18 – 2^29 . 3^20)/(5 . 2^28 . 3^19 – 7 . 2^29 . 3^18)`

   `= (2^29 . 3^18 . (5 . 2 – 3^2))/(2^28 . 3^18 . (5 . 3 – 7 . 2))`

   `= (2 . 1 . 1)/(1 . 1 . 1)`

   `= 2`

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2. Đáp án:

   `B=2`

   Giải thích các bước giải:

   `B=(5.4^15. 9^9-4. 3^20. 8^9)/(5.2^9. 6^19-7. 2^29 .27^6)`

   `=>B=(5.(2^2)^15.(3^2)^9-2^2. 3^20.(2^3)^9)/(5.2^9. (2.3)^19-7. 2^29.(3^3)^6`

   `=>B=(5. 2^30. 3^18-2^2. 3^20. 2^27)/(5.2^9. 2^19. 3^19-7. 2^29. 3^18`

   `=>B=(5.2^30. 3^18- 2^29. 3^20)/(5. 2^28. 3^19-7. 2^29. 3^18`

   `=>B=(2^29. 3^18(5.2-3^2))/(2^28. 3^18(5.3-7.2)`

   `=>B=2^29/2^28`

   `=>B=2

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