3,8 hay 3 và 8?

`2.(x+4)+5=65`

`=>2.(x+4)=65-5=60`

`=>x+4=60:2=30`

`=>x=30-4`

`=>x=26`

Tìm x

2 . (x + 4) + 5 = 65

2 . (x + 4) = 65 - 5

2 . (x + 4) = 60

(x + 4) = 60 : 2

(x + 4) = 30

x = 30 - 4

x = 26.

\(\dfrac{x+2}{2021}+\dfrac{x+3}{2020}=\dfrac{x+2021}{2}+\dfrac{x+2020}{3}\)

\(=>\dfrac{x+2}{2021}+1+\dfrac{x+3}{2020}+1=\dfrac{x+2021}{2}+1+\dfrac{x+2020}{3}+1\)

\(=>\dfrac{x+2+2021}{2021}+\dfrac{x+3+2020}{2020}=\dfrac{x+2021+2}{2}+\dfrac{x+2020+3}{3}\)

\(=>\dfrac{x+2023}{2021}+\dfrac{x+2023}{2020}-\dfrac{x+2023}{2}-\dfrac{x+2023}{3}=0\)

\(=>(x+2023)(\dfrac{1}{2021}+\dfrac{1}{2020}-\dfrac{1}{2}-\dfrac{1}{3})=0\)

  Mà \(\dfrac{1}{2021}+\dfrac{1}{2020}-\dfrac{1}{2}-\dfrac{1}{3} \ne 0\)

  \(=>x+2023=0\)

 \(=>x=-2023\)

Thanks

37 phút 15 giây :3=745 giây

7 phút 45 giây

7+2.(x-3)=11

2.(x-3)=11-7

x-3=4:2

x=2+3

x=5

`7+2.(x-3)=11`

`2.(x-3)=11-7`

`2.(x-3)=4`

`x-3=4:2`

`x-3=2`

`x=2+3`

`x=5`

Vậy `x=5`

`#LeMichael`

`541+(218-x)=73`

`=>541+218-x=73`

`=>759-x=73`

`=>x=759-73`

`=>x=686`

37,8 x195 = 7371

37,8 x 195 = 7371

https://olm.vn/cau-hoi/trong-khong-gian-oxyz-cho-2-diem-a210-va-b040-xet-diem-s-thay-doi-luon-thuoc-truc-oz-goi-k-la-trung-diem-sb-h-la-hinh-chieu-vuong-goc-cua.6496889055212

\(y'=3x^2-2\left(m+1\right)x-\left(m^2-2m\right)\)

Hàm nghịch biến trên (1;2) khi và chỉ khi \(y'\le0;\forall x\in\left(1;2\right)\)

\(\Leftrightarrow\left\{{}\begin{matrix}3.y'\left(1\right)\le0\\3.y'\left(2\right)\le0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}3-2\left(m+1\right)-\left(m^2-2m\right)\le0\\12-4\left(m+1\right)-\left(m^2-2m\right)\le0\end{matrix}\right.\)

\(\Leftrightarrow...\)

(2x+5).11=77

= 2x + 5 = 77:11

= 2x + 5 = 7

= 2x = 7-5

= 2 x = 2

= x = 2:2

= x = 1

(2x+ 5).11 = 77

(2x+5) = 77 :11

2x + 5 = 7

 2x = 7 -5

2x = 2

x = 2: 2

x = 1