Giup voi 3 . ( x + 1 ) + 2 . ( x + 2 ) = 5 5 . ( x + 6 ) + 6 . ( x + 1 ) = 47

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1. a) $3(x+1)+2(x+2)=5$

   $↔3x+3+2x+4=5$

   $↔5x+7=5$

   $↔5x=5-7=-2$

   $→x=-\dfrac{2}{5}$

   b) $5(x+6)+6(x+1)=47$

   $↔5x+30+6x+6=47$

   $↔11x+36=47$

   $↔11x=47-36=11$

   $→x=1$

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2.     `3(x+1)+2(x+2)=5`

   `⇒ 3x+3+2x+4=5`

   `⇒ 5x+7=5`

   `⇒ 5x=-2`

   `⇒ x=-2/5`

       `5(x+6)+6(x+1)=47`

   `⇒ 5x+30+6x+6=47`

   `⇒ 11x+36=47`

   `⇒ 11x=47-36=11`

   `⇒ x=1`

    

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