n(hh khí) = 0,093 (mol)

M_hh = 2.634/31 = 1268/31 (g/mol)

Đặt nN2O = a (mol)

      nN2 = b (mol)

=> \(\left\{{}\begin{matrix}a+b=0,093\\44a+28b=\dfrac{1268}{31}\cdot0,093=3,804\end{matrix}\right.\)

=> \(\left\{{}\begin{matrix}a=0,075\\b=0,018\end{matrix}\right.\)

Đặt nMg = x (mol); nAl = y (mol)

=> 24x + 27y = 7,74       (I)

BT e : 2x + 3y = 4.2.nN2O + 5.2.nN2

=> 2x + 3y = 0,78    (II)

Từ (I) và (II) => x = 0,12(mol) ; y = 0,18 (mol)

=> mMg = 2,88 (g)

=> B

\(\frac{1}{2}\): 3 + x = 1 \(\frac{2}{3}\)

\(\frac{1}{6}\)+ x = \(\frac{5}{3}\)

x = \(\frac{5}{3}\)- \(\frac{1}{6}\)

x = \(\frac{3}{2}\)

hố hố abcdeghiklmnopqrst

mèo

là sao , bn ghi đề dễ hiểu đc ko??

?

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

\(\left(x-1\right)^{x+2}-\left(x-1\right)^{x+4}=0\)

\(\left(x-1\right)^{x+2}\cdot1-\left(x-1\right)^{x+2}\cdot\left(x-1\right)^2=0\)

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

\(\Rightarrow\orbr{\begin{cases}\left(x-1\right)^{x+2}=0\\1-\left(x-1\right)^2=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x-1=0\\\left(x-1\right)^2=1=\left(\pm1\right)^2\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=1\\x=\left\{2;0\right\}\end{cases}}\)

Vậy.....

(x-1)^x+2 = (x-1)^x+4

=> (x-1)^x+2 - (x-1)^x+4 = 0

=> (x-1)^x+2. [ 1 - (x-1)² ] = 0

TH1: (x-1)^x+2 = 0

=> x - 1 = 0 => x  = 1

TH2: 1 - (x-1)² = 0 

=> (x-1)² = 1

=> x = 2 hoặc x = 0

KL: x = {0;1;2}

A = 2006 x 2006 x 2006

B = 2005 x 2006 x 2007

=> 2005 < 2006 ; 2006 < 2007 ; 2006 = 2006

=> 2006 x 2005 = 4022030

=> 2006 x 2006 =  4024036

=> 2006 x 2007 =  4026042

=> A > B

A>B vì 2016×2016>2015×2017

giải nhanh giúp mình vs gấp gấp