a) 5 ( x + 35 ) = 515

         x + 35 = 103

         x         = 68

b) 96 - 3(x+1) = 49 

           3(x+1) = 47

              x + 1 = 47/3

              x = 44/3

c) 12x - 33 = 3^2 * 3^3

     12x - 33 = 243

      12x = 276

          x = 23

5 ( x + 35 ) = 515

     x + 35  = 515 : 5

      x + 35 = 103

      x        = 103 - 35

      x         = 68

96 - 3( x + 1 ) = 49

       3( x + 1 ) = 96 - 49

        3( x + 1 ) = 47

            x + 1   = 47/3

            x         = 47/3 - 1 

             x        = 44/3

12x - 33 = 3² . 3³

12x - 33 = 3⁵

12x - 33 = 243

12x        = 243 + 33

12x        = 276

    x       = 276 : 12

     x       = 23

\(a.5\cdot\left(x+35\right)=515\)         

\(x+35=515:5\)

\(x+35=103\)

\(x=103-35\)      

x=68

\(b.96-3\left(x+1\right)=49\)  

\(3\left(x+1\right)=96-49\)         

\(3\left(x+1\right)=47\)

\(x+1=\frac{47}{3}\) 

\(x=\frac{47}{3}-1\)

\(x=\frac{44}{3}\)

\(c.12x-33=3^2\cdot3^3\)

\(12x-33=243\)

\(12x=243+33\)

\(12x=276\)

\(x=276:12\)

\(x=23\)

\(A=\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^3}+\dfrac{1}{3^4}+...+\dfrac{1}{3^{99}}\)

\(\Rightarrow\dfrac{A}{3}=\dfrac{1}{3^2}+\dfrac{1}{3^3}+\dfrac{1}{3^4}+...+\dfrac{1}{3^{100}}\)

\(\Rightarrow A-\dfrac{A}{3}=\dfrac{2A}{3}=\left(\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^3}+...+\dfrac{1}{3^{99}}\right)-\left(\dfrac{1}{3^2}+\dfrac{1}{3^3}+\dfrac{1}{3^4}+...+\dfrac{1}{3^{100}}\right)\)

\(\Rightarrow\dfrac{2A}{3}=\left(\dfrac{1}{3^2}-\dfrac{1}{3^2}\right)+\left(\dfrac{1}{3^3}-\dfrac{1}{3^3}\right)+...+\left(\dfrac{1}{3^{99}}-\dfrac{1}{3^{99}}\right)+\left(\dfrac{1}{3}-\dfrac{1}{3^{100}}\right)=\dfrac{1}{3}-\dfrac{1}{3^{100}}\)

\(\Rightarrow2A=3\cdot\left(\dfrac{1}{3}-\dfrac{1}{3^{100}}\right)\)

\(\Rightarrow\text{A}=\dfrac{1-\dfrac{1}{3^{99}}}{2}\)

\(\Rightarrow A=\dfrac{1}{2}-\dfrac{1}{2.3^{99}}< \dfrac{1}{2}\)

tụi mày ăn cái con khỉ ho cò gáy gì mà ko trà lời được ????

óc chó à ?

bạn giải đi

Chửi sang lên chứ bạn bạn óc chó ấy ko bt lm thì đăng nhờ ngta lm lm j mà chửi ngta

a.1872

b.3676

2 tui cũng là army yiu bts nhìu 

----jung hosoek---

a) 12 x 13 + 12 x 49 + 12 x 14 +14 x 78 = 1873

b) 34 x 34 + 56 x 45 = 3676

\(1.\text{ Tính : }\)

\(a,\text{ }12\text{ x }13+12\text{ x }49+12\text{ x }14+14\text{ x }78\)

\(=12\text{ x }\left(13+49\right)+14\text{ x }\left(12+78\right)\)

\(=12\text{ x }62+14\text{ x }90\)

\(=744+1260\)

\(=2004\)

\(b,\text{ }34\text{ x }34+56\text{ x }45\)

\(=1156+2520\)

\(=3676\)     

36 x 12 + 36 x 45 + 36 x 33

= 36 x (12 + 45 + 33)

= 36 x 90

= 3240

b) 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

=78 x (31 + 24 + 17) + 22 x 72

= 78 x 72 + 22 x 72

= (78 + 22) x 72

= 100 x 72

= 7200

c) ( 34 - 17 )² - 2³ x 3²

\(=17^2-8.9\)

\(=289-72\)

\(=217\)

d)11²⁰ : 11¹⁹ + 3⁰ x 3²

\(=11^{20-19}+0\cdot9\)

\(=11+0\)

\(=11\)

`@` `\text {Ans}`

`\downarrow`

`2023 \times 14 + 2023 \times 83+97`

`= 2023 \times (14+83) + 97`

`= 2023 \times 97 + 97`

`= 196231 +97`

`= 196328`

`78 \times 31+78 \times 24+78 \times 17+78 \times 22 \times 72`

`= 78 \times (31+24+17+22 \times 72)`

`= 78 \times (31+24+17+1584)`

`= 78 \times 1656`

`= 129168`

`371 \times 69+371 \times 14+629 \times 83`

`= 371 \times (69+14) + 629 \times 83`

`= 371 \times 83 + 629 \times 83`

`= 83 \times (371+629)`

`= 83 \times 1000`

`= 83000`

`91 \times 51+49 \times 163-49 \times 72`

`= 91 \times 51 + 49 \times (163-72)`

`= 91 \times 51+49 \times 91`

`= 91 \times (51+49)`

`= 91 \times 100`

`= 9100`

`3 \times 12 \times 17 + 4 \times 9 \times 81 + 2 \times 6 \times 6`

`= 9 \times 4 \times 17 + 4 \times 9 \times 81 + 4 \times 9 \times 2`

`= 9 \times 4 \times (17+81+2)`

`= 36 \times 100` 

`= 3600`

`42 \times 17 + 58 \times 83 \times 42 \times 83 + 42 \times 83 + 17`

`= 17 \times (42+58) + 42 \times 83 \times (58 \times 83 +1)`

`= 17 \times 100 + 3486 \times 4815`

`= 1700 + 16785090`

`= 16786790`

sao nhiều dậy sao lại nhiều thế làm cái này mà trong quan tài liền

1) \(8x^3-12x^2+6x-1=0\)

\(\Leftrightarrow\left(2x\right)^2-3\cdot\left(2x\right)^2\cdot1+3\cdot2x\cdot1^2-1^3=0\)

\(\Leftrightarrow\left(2x-1\right)^3=0\)

\(\Leftrightarrow2x-1=0\)

\(\Leftrightarrow2x=1\)

\(\Leftrightarrow x=\dfrac{1}{2}\)

2) \(x^3-6x^2+12x-8=27\)

\(\Leftrightarrow x^3-3\cdot x^2\cdot2+3\cdot2^2\cdot x-2^3=27\)

\(\Leftrightarrow\left(x-2\right)^3=27\)

\(\Leftrightarrow\left(x-2\right)^3=3^3\)

\(\Leftrightarrow x-2=3\)

\(\Leftrightarrow x=3+2\)

\(\Leftrightarrow x=5\)

3) \(x^2-8x+16=5\left(4-x\right)^3\)

\(\Leftrightarrow\left(x-4\right)^2=5\left(4-x\right)^3\)

\(\Leftrightarrow\left(4-x\right)^2=5\left(4-x\right)^3\)

\(\Leftrightarrow5\left(4-x\right)=1\)

\(\Leftrightarrow4-x=\dfrac{1}{5}\)

\(\Leftrightarrow x=4-\dfrac{1}{5}\)

\(\Leftrightarrow x=\dfrac{19}{5}\)

4) \(\left(2-x\right)^3=6x\left(x-2\right)\)

\(\Leftrightarrow8-12x+6x^2-x^3=6x^2-12x\)

\(\Leftrightarrow-12x+6x^2-6x^2+12x=8-x^3\)

\(\Leftrightarrow8-x^3=0\)

\(\Leftrightarrow x^3=8\)

\(\Leftrightarrow x^3=2^3\)

\(\Leftrightarrow x=2\)

5) \(\left(x+1\right)^3-\left(x-1\right)^3-6\left(x-1\right)^2=-10\)

\(\Leftrightarrow x^3+3x^2+3x+1-x^3+3x^2-3x+1-6\left(x^2-2x+1\right)=-10\)

\(\Leftrightarrow\left(x^3-x^3\right)+\left(3x-3x\right)+\left(3x^2+3x^2\right)+\left(1+1\right)-6x^2+12x-6=-10\)

\(\Leftrightarrow0+0+0+\left(6x^2-6x^2\right)+12x-4=-10\)

\(\Leftrightarrow12x-4=-10\)

\(\Leftrightarrow12x=-10+4\)

\(\Leftrightarrow12x=-6\)

\(\Leftrightarrow x=\dfrac{-6}{12}\)

\(\Leftrightarrow x=-\dfrac{1}{2}\)

6) \(\left(3-x\right)^3-\left(x+3\right)^3=36x^2-54x\)

\(\Leftrightarrow27-27x+9x^2-x^3-x^3-9x^2-27x-27=36x^2-54x\)

\(\Leftrightarrow-54x-2x^3=36x^2-54x\)

\(\Leftrightarrow-2x^3=36x^2\)

\(\Leftrightarrow-2x^3-36x^2=0\)

\(\Leftrightarrow-2x^2\left(x+18\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}-2x^2=0\\x+18=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-18\end{matrix}\right.\)