Bài 4 Tìm STN x a,131.x-941=27.$2^{4}$ a,131.x-941=27.$2^{4}$ b,[(x+32)-17].2=42 c,[($x^{2}$ + 54 )-32]:2=64

0 bình luận về “Bài 4 Tìm STN x a,131.x-941=27.$2^{4}$ a,131.x-941=27.$2^{4}$ b,[(x+32)-17].2=42 c,[($x^{2}$ + 54 )-32]:2=64”

1. a) $131x-941=27.2^4$

   $↔131x-941=27.16$

   $↔131x-941=432$

   $↔131x=432+941=1373$

   $↔x=\dfrac{1373}{131}(ktm)$

   b) $[(x+32)-17].2=42$

   $↔(x+32)-17=42:2=21$

   $↔x+32=21+17=38$

   $↔x=38-32=6(tm)$

   c) $[(x^2+54)-32]:2=64$

   $↔(x^2+54)-32=64.2=128$

   $↔x^2+54=128+32=160$

   $↔x^2=160-54=106$

   \(↔\left[ \begin{array}{l}x=\sqrt{106}(ktm)\\x=-\sqrt{106}(ktm)\end{array} \right.\)

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2. `a)131x-941=27.2^4`

   `⇒131x-941=27.16`

   `⇒131x-941=432`

   `⇒131x=432+941=1373`

   `⇒x=\dfrac{1373}{131}`(ko thỏa mãn)

   `b) [(x+32)-17].2=42`

   `⇒(x+32)-17=42:2=21`

   `⇒x+32=21+17=38`

   `⇒x=38-32=6`

   `c)[(x^2+54)-32]:2=64`

   `⇒(x^2+54)-32=64.2=128`

   `⇒x^2+54=128+32=160`

   `⇒x^2=160-54=106`

   \(⇒\left[ \begin{array}{l}x=√106\\x=-√106\end{array} \right.\)

    

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