9. (X + 0,7)^3 = -27 10. ( 2/3x -1/3)^5 = 1/243 11. ( (2/5-3X)^2 = 9/25 12. (2x-1)^10 = 49^5 13. X : 5^2 = (3/5)^2 : 3^2

0 bình luận về “9. (X + 0,7)^3 = -27 10. ( 2/3x -1/3)^5 = 1/243 11. ( (2/5-3X)^2 = 9/25 12. (2x-1)^10 = 49^5 13. X : 5^2 = (3/5)^2 : 3^2”

1. Đáp án + Giải thích các bước giải:

   9)

   `(x+0,7)^3=-27`

   `=>x+0,7=-3`

   `=>x=-3,7`

   10)

   `(2/3x-1/3)^5=1/243`

   `=>2/3x-1/3=1/3`

   `=>2/3x=2/3`

   `=>x=1`

   11)

   `(2/5-3x)^2=9/25`

   `=>2/5-3x=3/5` hoặc `2/5-3x=-3/5`

   `=>3x=-1/5` hoặc `3x=1`

   `=>x=-1/15` hoặc `x=1/3`

   Vậy `x∈{-1/15;1/3}`

   12)

   `(2x-1)^10=49^5`

   `=>(2x-1)^10=(7^2)^5`

   `=>(2x-1)^10=7^10`

   `=>2x-1=7`

   `=>2x=8`

   `=>x=4`

   13)

   `x:5^2=(3/5)^2:3^2`

   `=>x:25=9/25:9`

   `=>x:25=1/25`

   `=>x=1`

    

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2. 9. `(x+0,7)^3 = -27`

   `(x+0,7)^3 = (-3)^3`

   `⇒ x+0,7 = -3`

   `⇒ x = -3,7`

   10. `(2/3x – 1/3)^5 = 1/243`

   ` ( 2/3x -1/3)^5 = (1/3)^5`

   `⇒ 2/3x – 1/3 = 1/3`

   `⇒ 2/3x = 2/3`

   `⇒ x = 1`

   11. `(2/5-3X)^2 = 9/25`

   `(2/5-3x)^2 = (3/5)^2`

   `⇒ 2/5 – 3x = 3/5`

   `⇒ 3x = -1/5`

   `⇒ x = -1/15`

   12. ` (2x-1)^10 = 49^5`

   `⇒ (2x-1)^10 = (7^2)^5 = 7^10`

   `⇒ 2x-1=7`

   `⇒ 2x=8`

   `⇒ x = 4`

   13. `x : 5^2 = (3/5)^2 : 3^2`

   `x : 5^2 = (3/5 : 3)^2`

   `x:5^2 = 1/25`

   `x = 1`

    

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