Tìm x biết ( x-0)^6-(x-2)^8=0 30.(x+2)-6.(x-5)-22x=100

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1. ` (x – 0)^6 – (x – 2)^8 = 0 `

   ` <=> x^6 – [(x – 2)^2]^4 = 0 `

   ` <=> (x^2)^3 – [(x – 2)^2]^4 = 0 `

   ` <=> (2x – 2)^3 . (0 – 2)^4 = 0 `

   ` <=> (2x – 2)^3 . (-2)^4 = 0 `

   ` <=> (2x – 2)^3 . 16 = 0 `

   ` <=> (2x – 2)^3 = 0 `

   ` <=> 2x – 2 = 0 `

   ` <=> 2x = 2 `

   ` <=> x = 1 `

   ` 30(x + 2) – 6(x – 5) – 22x = 100 `

   ` <=> 30x + 60 – 6x + 30 – 22x = 100 `

   ` <=> 30x – 6x – 22x + 60 + 30 = 100 `

   ` <=> 2x + 90 = 100 `

   ` <=> 2x = 10 `

   ` <=> x = 5 `

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2. Đáp án:

   $( x-0)^6-(x-2)^8=0$

   $⇔x^6 – (x-2)^8 = 0$

   $⇔ (x^2)^{3} – [(x-2)^2]^{4} = 0$

   $⇔ (x+x-2)^3.(x-x-2)^4= 0$

   $⇔[ (2x-2)]^{3} .[(0x-2)]^{4}=0$

   $⇔(2x-2) =0$

   $⇔ 2x =2$ 

   $⇔x = 1$

   $\text{Hoặc }$

   $0x -2 =0$

   $⇔0x = 2(vô lí)$

   $\text{Vậy x= 1 }$

   $30 .(x+2)-6(x-5)-22x= 100$

   $⇔ 30x + 60 – 6x + 30 -22x = 100$

   $⇔30x -6x -22x = 100 -30 -60$

   $⇔ 2x = 10$

   $⇔ x = 10 : 2$

   $⇔ x = 5$

   $\text{Vậy}$$ x =5 $

    

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