Ta có: \(\left|x-2\right|+\left|x-20\right|+\left|x-38\right|\)

\(=\left|x-2\right|+\left|x-20\right|+\left|38-x\right|\)

\(\ge\left|x-2+38-x\right|+0=36+0=36\)

Dấu "=" khi x = 20

Use the correct form of the past simple passive or the present perfect passive

1. In the First World War, radios ......used.......... (use) to communicate with soldiers

2. Since the 1960s, many radios signals...........have been sent........ (send) into outer space

3. So far, no answers ...........have been received​............... (receive) from other planets

4. It's possible that the signals have arrived on other planets, but the messages ..........have not understood.​.............. (not understand)

# HOK TỐT #

x = 4¹⁶ . 5²⁵ = (2²)¹⁶ . 5²⁵ = 2³² . 5³² . 5³ = 10³² . 5³ = 12500000….000

suy ra x có 32 + 3 = 35 chs (10³² có 32 chữ số 0 mà 125 nhân vs 10³² nên số 1 thay thế = số 125 thành là 32 + 3 = 35)

bạn oi 5\(^{25}\)ma

thay 108 = x - 1 vào M là ra nha

thế ra bao nhiêu ạ

Ta có:

4ⁿ⁺³ +4ⁿ⁺² -4ⁿ⁺¹ -4ⁿ 

=4^n-1 .4⁴ + 4^n-1 . 4³ - 4^n-1 . 4² - 4^n-1 .4 

=4^n-1 . (4⁴  +4³ - 4² -4) 

=4^n-1 . 300 : 300 

= 4ⁿ⁺³  + 4ⁿ⁺² -4ⁿ⁺¹  -4ⁿ \(⋮\) 300 (ĐPCM)

Đặt A=4^{n+3}+4^{n+2}-4^{n+1}-4^n

A= 4^n-1(4^4+4^3-4^2-4)

A=4^n-1.300⋮300

                  k cho mik nha                học tốt.

Áp dụng tc của dãy tỉ số bằng nhau :

\(\frac{2.\left(x-1\right)}{4}=\frac{3.\left(y-2\right)}{9}=\frac{z-3}{4}=\frac{2x+3x-z-2-6+3}{4+9-4}=\frac{90}{9}=10\)

\(=>\hept{\begin{cases}\frac{x-1}{2}=10=>x-1=20=>x=21\\\frac{y-2}{3}=10=>y-2=30=>y=32\\\frac{z-3}{4}=10=>z-3=40=>z=43\end{cases}}\)

Vậy ...

Trả lời:

\(\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{4}\)

Đặt\(\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{4}=k\)

\(\Rightarrow\hept{\begin{cases}x-1=2k\\y-2=3k\\z-3=4k\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}x=2k+1\\y=3k+2\\z=4k+3\end{cases}}\)

Mà\(2x+3y-z=95\)

\(\Rightarrow2\left(2k+1\right)+3\left(3k+2\right)-\left(4k+3\right)=95\)

\(\Leftrightarrow4k+2+9k+6-4k-3=95\)

\(\Leftrightarrow9k+5=95\)

\(\Leftrightarrow9k=90\)

\(\Leftrightarrow k=10\)

\(\Rightarrow\hept{\begin{cases}x=2.10+1=21\\y=3.10+2=32\\z=4.10+3=43\end{cases}}\)(Thỏa mãn)

Vậy\(\hept{\begin{cases}x=21\\y=32\\z=43\end{cases}}\)

Hok tốt!

Good girl

Tự vẽ hình nha

a) ABD và EBD có: abd = ebd (bd la phân giác), BD chung

=> bằng nhau (cạnh huyền - góc nhọn)

=> AB = Be (2 cạnh tương ứng) => abe cân

b) ta có: AD = DE (vì tg ABD = tg EBD) mà DE < CD (Cạnh huyên là cạnh lớn nhất) nên AD < CD (ĐPCM)

Còn câu c,d thì sao bạn?

1. How beautiful the buildings are!

2. How much is the bicycle?

3. I used to collect stamps when I was in primary school.

4. Mr. Hung is a fluent Chinese speaker.

Viết lại câu với nghĩa không đổi:

1. What beautiful  buildings!

=> How ..beautiful the building are...............

2. What is the price of the bicycle?

=> How much ..does the bicycle cost.......

3. I don't have time to collect stamps as when I was in primary school.

=> I uesd to collect stamps as when I was in primary school..............

4. Mr. Hung speaks Chinese fluently.

=> Mr. Hung is ..a fluent Chinese speaker.................