Tính : 81^4.3^10.27^5:3^12/9^9:9^3.243^2 Tìm x: |2-3/2.x|- 4 =x+2

Đáp án:

 `↓↓`

Giải thích các bước giải:

`a) `

`(81^4. 3^10. 27^5 : 3^12)/(9^9 :9^3. 243^2)`

`=((3^4)^4. 3^10. (3^3)^5 :3^12)/((3^2)^9 :(3^2)^3. (3^5)^2)`

`=(3^16. 3^10. 3^15 :3^12)/(3^18 : 3^6. 3^10)`

`=(3^(41): 3^12)/(3^(28): 3^6)=(3^(29))/(3^(22))=3^7`=2187`

`b)`

`|2-3/2. x|-4=x+2`

`=> |2-3/2. x|=x+2+4`

`=> |2-3/2. x|=x+6`

`=>` \(\left[ \begin{array}{l}2-\dfrac{3}{2}x=x+6\\2-\dfrac{3}{2}x=-x-6\end{array} \right.\)   `=>` \(\left[ \begin{array}{l}2-6=x+\dfrac{3}{2}x\\2+6=-x+\dfrac{3}{2}x\end{array} \right.\) `=>` \(\left[ \begin{array}{l}-4=\dfrac{5}{2}x\\8=\dfrac{1}{2}x\end{array} \right.\)

`=>` \(\left[ \begin{array}{l}x=\dfrac{-8}{5}\\x=16\end{array} \right.\)