x-12=24+50

x-12=74

x=74+12

x=86

x+12=24+50

x+12=74

x=74-12

x=62

tk nha bạn

x - 12 = 24 + 50

x - 12 = 74

x        = 74 + 12

x        = 86

x + 12 = 24 + 50

x + 12 = 74

x         = 74 - 12

x         = 62

x-12=24+50

x-12=74

x=74+12

x=86

x+12=24+50

x+12=74

x=74-12

x=62

a) Ta có B (12) = {0;12;24;36;48;60;72,..}. Mà 20 ≤ x ≤ 50 ;

=> xϵ {24;36;48}.

b) x ϵ {10;20}.

c) x ϵ {0;7;14;21;28;35;42;49}.

d) x ϵ {1;2;3;4;6;12

x + 12 x 2 = 50 + 50

x + 12 x 2 = 100

x + 24 = 100

        x = 100 - 24

        x = 76

x + 12 x 2 = 50 + 50

x+12x2=100

x+24=100

x=100-24

x=76

x + 12 x 2 = 50 + 50

x + 24 = 100

x = 100 - 24

x = 76

k mk nha

=-12*(14-3+50)+168-36

=-12*61+132

=-600

x = 60 , 72

đúng

trả lời giúp mình

x⋮12 ⇒x∈B(12)

B(12)={0;12;24;36;48;60;72;...}

Vì 50<x\(\le\)72

nên x∈{60;72}

\(\Leftrightarrow\dfrac{x}{50}-\dfrac{x}{55}-\dfrac{12}{55}=1\)

\(\Leftrightarrow x\left(\dfrac{1}{50}-\dfrac{1}{55}\right)=1+\dfrac{12}{55}\)

\(\Leftrightarrow\dfrac{x}{550}=\dfrac{67}{55}\)

\(\Leftrightarrow x=670\)

Lời giải:

Vì $x$ là STN, $x\in B(12)$ nên $x\in\left\{0; 12; 24; 36; 48; 60;...\right\}$

Mà $x<50$ nên $x\in\left\{0; 12; 24; 36;48\right\}$

\(x\in B\left(12\right)\)

Mà: \(B\left(12\right)=\left\{0;12;24;36;48;60;72;84;96;108;...\right\}\)

Và: \(x< 50\)

\(\Rightarrow x\in\left\{0;12;24;36;48\right\}\) 

\(a,71-3(12-x)=125\\3(12-x)=71-125\\3(12-x)=-54\\12-x=-54:3\\12-x=-18\\x=12-(-18)\\x=30\\---\)

\(b,3(12+x)-41=-50\\3(12+x)=-50+41\\3(12+x)=-9\\12+x=-9:3\\12+x=-3\\x=-3-12\\x=-15\\---\)

\((14+2x)-34=-28\\14+2x=-28+34\\14+2x=6\\2x=6-14\\2x=-8\\x=-8:2\\x=-4\\Toru\)

      3(12 - x) = 71 - 125

       3(12 - x) = -54

          12 - x = -54 : 3

           12 -x = -18

            x = 12 + 18

            x = 30

b) 3(12+x)- 41= -50

   3(12 + x) = -50 + 41

   3(12 - x) = -9

   12 - x = -9 : 3

   12 - x = -3

    x = 12 + 3

    x = 15

c)(14+2x)-34=-28

  ( 14 + 2x) = -28 + 34

  (14 + 2x)  = 6

  2x = 6 - 14

  2x = -8

 x = -8 : 2

  x = -4 

--thonezz--

Tớ sửa lại câu b nhé 😥( tớ viết lộn đề  :( )

b) 3(12+x)- 41= -50

   3(12 + x) = -50 + 41

   3(12 + x) = -9

   12 + x = -9 : 3

   12 +  x = -3

    x =  -3 -12

     x = -15

(x + 2) + (x + 5) +(x + 7) +(x + 12) + (x + 19) + (x + 31) + (x+50)+(x+81) = 233,4

8x+(2+5+7+12+19+31+50+81)=233,4

8x+207=233,4

8x=26,4

Vậy =3,3

chúc bạn học tốt ^-^