Mờ quá em ơi

Xét ΔMNO có \(\hat{M}+\hat{N}+\hat{O}=180^0\)

=>\(\hat{M}=180^0-\hat{N}-\hat{O}=180^0-\hat{A}-\hat{C}\) (1)

Xét ΔBAC có \(\hat{B}+\hat{A}+\hat{C}=180^0\)

=>\(\hat{B}=180^0-\hat{A}-\hat{C}\left(2\right)\)

Từ (1),(2) suy ra \(\hat{M}=\hat{B}\)

\(\frac{BC}{MN}=\frac24=\frac12;\frac{BA}{MO}=\frac{2.5}{5}=\frac12;\frac{AC}{NO}=\frac36=\frac12\)

Xét ΔMNO và ΔBCA có

\(\frac{MN}{BC}=\frac{NO}{AC}=\frac{MO}{AB}\left(\frac42=\frac63=\frac{5}{2,5}=2\right)\)

Do đó: ΔMNO~ΔBCA

mờ mờ ảo ảo , nhìn lác mắt!

Ok

8⁸+2²⁰=(2³⁾⁸+2²⁰=2²⁴+2²⁰=2²⁴(2¹⁶+1)=2²⁴x17chia het cho 17

ra 34 và - 20 

mk làm rùi đó ,bài dưới ế ,rõ ràng rành mạch lên pạn mk nha 

|7- x|=(-13)-5.(-8)

|7- x|=144

7- x=144

      x=7-144

        x=(-137)

Vậy : x=(-137); x=137

Bài 1 : 

\(CT:C_nH_{2n-6}\left(n\ge6\right)\)

\(\%C=\dfrac{12n}{14n-6}\cdot100\%=90.57\%\)

\(\Rightarrow n=8\)

\(CT:C_8H_{10}\)

Bài 2 : 

\(n_{CO_2}=\dfrac{17.6}{44}=0.4\left(mol\right)\)

\(CT:C_nH_{2n+1}OH\)

\(\Rightarrow n_{ancol}=\dfrac{n_{CO_2}}{n}=\dfrac{0.4}{n}\left(mol\right)\)

\(M_A=\dfrac{7.4}{\dfrac{0.4}{n}}=\dfrac{37}{2}n\left(\dfrac{g}{mol}\right)\)

\(\Rightarrow14n+18=\dfrac{37}{2}n\)

\(\Rightarrow n=4\)

\(CT:C_4H_9OH\)

\(CTCT:\)

\(B1:\)

\(CH_3-CH_2-CH_2-CH_2-OH:butan-1-ol\)

\(B2:\)

\(CH_3-CH_2-CH\left(CH_3\right)-OH:butan-2-ol\)

\(B2:\)

\(CH_3-CH\left(CH_3\right)-CH_2-OH:2-metylpropan-1-ol\)

\(B3:\)

\(C\left(CH_3\right)_3-OH:2-metylpropan-2-ol\)

Bài 1 : 

CTPT X:  C_nH_2n-6

Ta có :

\(\%C = \dfrac{12n}{14n-6}.100\% = 90,57\%\\ \Rightarrow n = 8\)

Vậy CTPT của X: C₈H₁₀

x:54+x:16=217

x:(54+16)=217

x:70=217

x   =217*70

x   =15190

x:[16=54] =217

x ; 70 =217

x =217 nhân 70 = 15190

x = 15190

Me: What are you doing on Sunday afternoon?

Friend: I’m not doing anything. / Nothing much.

Me: Do you want to see a movie with me?

Friend: Sure. What movie is it?

Me: It's "The Journey to Mars".

Friend: What time does it start?

Me: It starts at 4 p.m.

Friend: Great! See you then.

Me: What are you doing on Saturday morning?

Friend: I’m free.

Me: Would you like to go to the movies with me?

Friend: Sounds good. What movie do you want to watch?

Me: How about "The Forest Book"?

Friend: What time is it on?

Me: It's at 10 a.m.

Friend: OK, let's meet at the cinema at 9:45.

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~ Hok tốt , nhớ tk mik nha ~

theo mk thì bạn nên tham khảo tech12 "soạn toán 7 vnen tech12" nếu bạn học chương trình ms  nha^^