K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

27 tháng 7 2018

h) Ta có: \(\left\{{}\begin{matrix}\left|x-7\right|=\left|7-x\right|\ge7-x\\\left|x+5\right|\ge x+5\end{matrix}\right.\)

\(\Rightarrow\left|7-x\right|+\left|x+5\right|\ge\left(7-x\right)+\left(x+5\right)\)

\(\Rightarrow\left|x-7\right|+\left|x+5\right|\ge12\)

\(\Rightarrow H\ge12\)

Dấu "=" xảy ra \(\Leftrightarrow\left\{{}\begin{matrix}7-x\ge0\\x+5\ge0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x\le7\\x\ge-5\end{matrix}\right.\)

\(\Leftrightarrow-5\le x\le7\)

Vậy, MinH = 12 \(\Leftrightarrow-5\le x\le7\)

27 tháng 7 2018

a) Ta có: \(A=2x^2-8x+10\)

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

\(=2\left(x^2-4x+2^2+1\right)\)

\(2\left[\left(x-2\right)^2+1\right]\)

Ta lại có: \(\left(x-2\right)^2\ge0\)

\(\Rightarrow2\left[\left(x-2\right)^2+1\right]\ge2\)

\(\Rightarrow A\ge2\)

Dấu bằng xảy ra \(\Leftrightarrow\left(x-2\right)^2=0\)

\(\Leftrightarrow x-2=0\)

\(\Leftrightarrow x=2\)

Vậy MinA = 2 \(\Leftrightarrow x=2\)

17 tháng 7 2017

II. Make sentences from the given words or phrases: 1. There/ a bed / corner/ the room .......................THERE IS A BED AT THE CORNER OF THE ROOM.............. 2. Shelves/ above/ the closet .............THE SHELVES ABOVE IS THE CLOSET........................ 3. Wardrobe/ the center/ the room ........A WARDOBE IS ON THE CENTER OF THE ROOM............................. 4. Table/ between/ two chairs ...................THERE IS A TABLE BETWEEN TWO CHAIRS.................. 5. Lamp/next/the bed ............THE LAMP IS NEXT TO THE BED......................... 6. Table / the right/the wardrobe ..........THE TABLE IS ON THE RIGHT OF THE WARDROBE........................... 7. There / some pictures/ the wall .........THERE ARE SOME PICTURES ON THE WALL............................ 8. There/ a window/ the left-side / the room ..........THERE IS A WINDOWW ON THE LEFT-SIDE OF THE ROOM........................... 9. Bed/ opposite/ the door ............THE BED IS OPPOSITE THE DOOR......................... 10. There/ some bottles/ the shelf .......................THERE ARE SOME BOTTLES ON THE SHELFF..............

17 tháng 7 2017

II. Make sentences from the given words or phrases:

1. There/ a bed / corner/ the room ....................There is a bed at the corner of the room.................

2. Shelves/ above/ the closet ..................The shelves are above the closet..................

3. Wardrobe/ the center/ the room ..................The wardrobe is at the center of the room...................

4. Table/ between/ two chairs ...................The table is between two chairs..................

5. Lamp/next/the bed ...................The lamp is next to the bed..................

6. Table / the right/the wardrobe ....................The table is to the right of the wardrobe.................

7. There / some pictures/ the wall ...................There are some pictures on the wall..................

8. There/ a window/ the left-side / the room ....................There is a window on the left-side of the room.................

9. Bed/ opposite/ the door ...................The bed is opposite the door..................

10. There/ some bottles/ the shelf ....................There are some bottles on the shelf.................

29 tháng 7 2018

Bạn nào cho mk 1 ik, mk cho bn ý 3 ik luôn. Mk hứa nếu nói dối bạn có thể Báo cáo sai phạm mk.