\(2.16\ge2^n>4\)

\(2.2^4\ge2^n>2^2\)

\(2^5\ge2^n>2^2\)

=> \(n\in\left\{3,4,5\right\}\)

Vậy: \(n\in\left\{3,4,5\right\}\)

x-38+ 12x 16
x-12+=...
x=...+12 
x=...

g, (x-38) : 16 = 12

    (x-38)        = 12 . 16

    (x-38)        = 192

     x               = 192 + 38

     x               = 230

Vậy x = 230.

\(\Leftrightarrow x-38=192\)

hay x=230

\(\Leftrightarrow5x=45\)

hay x=9

5x=45

x=9

\(\Rightarrow5x=69-24=45\\ \Rightarrow x=\dfrac{45}{5}=9\)

g: \(x\left(x-5\right)-3\left(x-5\right)=\left(x-5\right)\left(x-3\right)\)

h: \(x\left(x-y\right)-2\left(y-x\right)=\left(x-y\right)\left(x+2\right)\)

i: \(x\left(x+3\right)+5\left(x+3\right)=\left(x+3\right)\left(x+5\right)\)

k: \(m\left(x-3\right)-n\left(x-3\right)=\left(x-3\right)\left(m-n\right)\)

l: \(5x-10=5\left(x-2\right)\)

\(a)5m-5n=5(m-n)\\b) -2x-2y=-2(x+y)\\c)-7+7y=-7(1-y)\\d)10x^3-15x^2=5x^2(2x-3)\\e) x^2-xy=x(x-y)\\f)9x^4-6x^2=3x^2(3x^2-2)\\g)x(x-5)-3(x-5)=(x-3)(x-5)\\h)x(x-y)-2(y-x)=x(x-y)+2(x-y)=(x+2)(x-y)\\i)x(x+3)+5(3+x)=(x+5)(x+3)\\k)m(x-3)+n(3-x)=m(x-3)-n(x-3)=(m-n)(x-3)\\l)5x-10=5(x-2) \)

giúp tớ với, tớ đang cần gấp lắm ạ.

CT : CnH2n+1OH

nCO2 = 13.2/44 = 0.3 (mol) 

nH2O = 7.2/18 = 0.4 (mol) 

CnH2n+1OH + 3n/2O2  -to-> nCO2 + (n+1)H2O

...........................................n............n+1

...........................................0.3...........0.4

=> 0.4n = 0.3(n+1) 

=> n = 3 

CTPT : C3H7OH 

CTCT : 

CH3 - CH2 - CH2 - OH : propan - 1 - ol 

CH3 - CH(CH3)-OH : propan - 2 - ol 

Gọi CTHH HC là \(XO_2\)

Ta có \(PTK_{XO_2}=NTK_X+2\cdot NTK_O=32\cdot PTK_{H_2}\)

\(\Leftrightarrow NTK_X=32\cdot2-2\cdot16=32\left(đvC\right)\)

Do đó X là lưu huỳnh (S)

biết \(PTK\) của \(H_2=2.1=2\left(đvC\right)\)

vậy \(PTK_X=2.32=64\left(đvC\right)\)

ta có:

\(1X+2O=64\)

\(X+2.16=64\)

\(X+32=64\)

\(X=64-32=32\left(đvC\right)\)

\(\Rightarrow X\) là lưu huỳnh, kí hiệu là \(S\)

P/S: đây là chi tiết cụ thể, ko thì bạn làm như anh Nguyễn Hoàng Minh cũng được!