\(\dfrac{1}{3}+\dfrac{5}{6}\cdot\left(x-\dfrac{11}{5}\right)=\dfrac{3}{4}\)

\(\dfrac{5}{6}\cdot\left(x-\dfrac{11}{5}\right)=\dfrac{3}{4}-\dfrac{1}{3}\)

\(\dfrac{5}{6}\cdot\left(x-\dfrac{11}{5}\right)=\dfrac{5}{12}\)

\(x-\dfrac{11}{5}=\dfrac{5}{12}\cdot\dfrac{6}{5}\)

\(x-\dfrac{11}{5}=\dfrac{1}{2}\)

\(x=\dfrac{1}{2}+\dfrac{11}{5}\)

\(x=\dfrac{27}{10}\)

\(\dfrac{5}{6}\left(x-\dfrac{11}{5}\right)=\dfrac{3}{4}-\dfrac{1}{3}\)

\(\dfrac{5}{6}\left(x-\dfrac{11}{5}\right)=\dfrac{5}{12}\)

\(x-\dfrac{11}{5}=\dfrac{5}{12}:\dfrac{5}{6}\)

\(x-\dfrac{11}{5}=\dfrac{1}{2}\)

\(x=\dfrac{1}{2}+\dfrac{11}{5}=\dfrac{27}{10}\)

`@` `\text {Ans}`

`\downarrow`

\(\dfrac{1}{3}+\dfrac{5}{6}\times\left(x-\dfrac{11}{5}\right)=\dfrac{3}{4}\)

\(\dfrac{5}{6}\times\left(x-\dfrac{11}{5}\right)=\dfrac{3}{4}-\dfrac{1}{3}\)

\(\dfrac{5}{6}\times\left(x-\dfrac{11}{5}\right)=\dfrac{5}{12}\)

\(x-\dfrac{11}{5}=\dfrac{5}{12}\div\dfrac{5}{6}\)

\(x-\dfrac{11}{5}=\dfrac{5}{12}\times\dfrac{6}{5}\)

\(x-\dfrac{11}{5}=\dfrac{6}{12}\)

\(x=\dfrac{6}{12}+\dfrac{11}{5}\)

\(x=\dfrac{27}{10}\)

Bạn có sai đề không vậy? Nếu đúng ra phải là  (a + 1) + (a + 2) + (a + 3) + (a + 4) + (a + 5) = 115 chứ 

Nếu bạn sai đề thì mình giải nè:

a x 5 + (1 + 2 + 3 + 4 + 5) = 115
a x 5 + 15 = 115
a x 5 = 100
a     = 100 :5
a     = 20

a) Ta có: \(\left(x+5\right)\left(x-4\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x+5=0\\x-4=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=-5\\x=4\end{matrix}\right.\)

Vậy \(\left[{}\begin{matrix}x=-5\\x=4\end{matrix}\right.\).

b) \(\left(3-x\right)\left(x-3\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}3-x=0\\x-3=0\end{matrix}\right.\) \(\Rightarrow x=3\)

Vậy \(x=3\).

c) \(5\left(x+1\right)-3^2=3\left(2+x\right)-8\)

\(\Rightarrow5x+5-9=6+3x-8\)

\(\Rightarrow5x-3x=-5+9-8\)

\(\Rightarrow2x=-4\)

\(\Rightarrow x=-2\)

Vậy \(x=-2.\)

giúp mk câu này nha

x . ( x + 1 ) = 0

-12 . ( x - 5 ) + 7. ( 3 - x ) = 5

- 12x - ( - 60 ) + 21 - 7x = 5

- 12x + 60 + 21 - 7x = 5

- 12 x + 81 - 7x = 5

- 12x - 7x = 5 - 81

- 12x - 7x = - 76

( - 12 - 7 ).x = - 76

- 19 . x = -76

x = - 76 : ( - 19 )

x = 4

Vậy x = 4

-12.(x - 5) + 7.(3 - x) = 5

(-12).x - (-12).5 + 7.3 - 7x = 5

(-12).x + 60 + 21 - 7x = 5

(-12).x - 7x = 5 - 60 - 21

(-19).x = -76

x = (-76) : (-19)

x = 4

1 + 2 + 3 + ... + x = 55

=> (x + 1) . x : 2 = 55

=> (x + 1) . x = 55 . 2

=> (x + 1) . x = 110

=> (x + 1) . x = 11 . 10

=> (x + 1) . x = (10 + 1) . 10

=> x = 10.

<=> x(x + 1) : 2 = 55

<=> x(x + 1) = 55.2

<=> x(x + 1) = 110

<=> x(x + 1) = 10.11

<=> x(x + 1) = 10(10 + 1)

=> x = 10

2^x+2^x+3=2^x+2^x.8

=2^x.9=144

=> 2^x=8=>x=3

b, 2(x-5)+3(x-7)=2x-10+3x-21=10=>5x-31=10=>5x=41

=> x=8,2

Ta có: \(3-2\left(x+1\right)=51\)

\(\Rightarrow2\left(x+1\right)=3-51\)

\(\Rightarrow2\left(x+1\right)=-48\)

\(\Rightarrow x+1=-48:2\)

\(\Rightarrow x+1=-24\)

\(\Rightarrow x=-24-1\)

\(\Rightarrow x=-25\)

Vậy \(x=-25.\)

\(3-2.\left(x+1\right)=51\)

\(2.\left(x+1\right)=3-51\)

\(2.\left(x+1\right)=-48\)

\(x+1=-48:2\)

\(x+1=-24\)

\(x=-24+1\)

\(x=-23\)

Hoàng Thị Ngọc Anh đúng r đó :)

a,Nghiệm của (2\(x\) - 5)²⁰²² là giá trị của \(x\) thỏa mãn

  (2\(x\) - 5)²⁰²² = 0

   2\(x\) -  5 = 0

  2\(x\)        = 5

  2\(x\)       = 5:2

   \(x\)        = 2,5

b, Nghiệm của (3\(x\) + 4)²⁰²⁴ là giá trị của \(x\) thỏa mãn:

(3\(x\) + 4)²⁰²⁴ = 0

    3\(x\) + 4 = 0

    3\(x\)       = -4

   \(x\)       = - 4 : 3

   \(x\) = -\(\dfrac{4}{3}\)

Bn ơi sai đề say sao ý !

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