1. Tìm x a, x + 7=-12 b, x – 15 = – 21 c, 13 – x = 20 2. Tìm x a, 17 – ( 2+x ) = 3 b, ( 6+x ) – ( 17-21) =- 25 c, -10 – ( 31-x ) =40

0 bình luận về “1. Tìm x a, x + 7=-12 b, x – 15 = – 21 c, 13 – x = 20 2. Tìm x a, 17 – ( 2+x ) = 3 b, ( 6+x ) – ( 17-21) =- 25 c, -10 – ( 31-x ) =40”

1. 1. Tìm x

   `a,x+7=-12`
   `->` `x=-12-7`
   `->` `x=-19`

   `b,x-15=-21`

   `->` `x=-21+15`

   `->` `x=-6`

   `c,13-x=20`

   `->` `x=13-20`

   `->` `x=-7`

   2.Tìm x

   `a,17-(2+x)=3`
   `->` `2+x=17-3`

   `->` `2+x=14`

   `->` `x=14-2`

   `->` `x=12`

   `b,(6+x)-(17-21)=-25`

   `->“(6+x)-(-4)=-25`

   `->“(6+x)=-25+(-4)`

   `->“(6+x)=-29`

   `->` `x=-29-6`

   `->` `x=-35`

   `c,-10-(31-x)=40`

   `->`    `31-x=-10-40`

   `->`    `31-x=-50`

   `->`    `x=31-(-50)`

   `->`    `x=81`

   $#@Sanchy2008 Xin hay nhất ạ$

    

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2. Đáp án:

    1.

   a, x = -19

   b, x = -6

   c, x = -7

   d

   2.

   a, x = 12

   b, x = -35

   c, x = 81

   Giải thích các bước giải:

    1. Tìm x

   `a,x+7=-12`

   `=>` $\text{x = -12 – 7}$

   `=>`$\text{x = -19}$

   $\text{b, x – 15 = – 21}$

   `=>`$\text{x = – 21 + 15}$

   `=>`$\text{x = -6}$

   $\text{c, 13 – x = 20}$

   `=>`$\text{x = 13 – 20}$

   `=>`$\text{x = -7}$

   2. Tìm x

   $\text{a, 17 – ( 2+x ) = 3}$

   `=>`$\text{2 + x = 17 – 3}$

   `=>`$\text{2 + x = 14}$

   `=>`$\text{x = 14 – 2}$

   `=>`$\text{x = 12}$

   $\text{b, ( 6+x ) – ( 17-21) =- 25}$

   `=>`$\text{(6+x) – (-4) = -25}$

   `=>`$\text{(6+x) + 4 = -25}$

   `=>`$\text{6 + x = -25-4}$

   `=>`$\text{6 + x = -29}$

   `=>`$\text{x = -29-6}$

   `=>`$\text{x = -35}$

   $\text{c, -10 – ( 31-x ) =40}$

   `=>`$\text{31 – x = -10-40}$

   `=>`$\text{31 – x = -50}$

   `=>`$\text{x = 31 – (-50)}$

   `=>`$\text{x = 31 + 50}$

   `=>`$\text{x = 81}$

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