\(\frac{1}{2}.2^n+4.2^n=9.2^5\)

\(\Rightarrow\left(\frac{1}{2}+4\right).2^n=9.2^5\)

\(\Rightarrow\frac{9}{2}.2^n=9.2^5\)

\(\Rightarrow9.2^{n-1}=9.2^5\)

\(\Rightarrow2^{n-1}=2^5\)

\(\Rightarrow n-1=5\)

\(\Rightarrow n=6\)

cảm ơn bạn chúc bạn hok tốt

A,    (-1/3)^2 .(-1/3) 
= (-1/3)^2+1
= (-1/3)^3
= -1/27
B, (-2)^2.(-2)^3 = (-2)^2+3 = (-2) ^ 5 = -32
C, a^5. a^7 = a^5+7 =a^12 
Ok nhé bạn !

\(\left|x-1\right|-2^3>59^0=1\)

\(\Leftrightarrow\left|x-1\right|>1+2^3=9\)

TH1 : \(x-1>9\Leftrightarrow x>10\)

TH2 : \(1-x>9\Leftrightarrow x< -8\)

\(\left|x-1\right|< 5-7=-2\)( vô lí ) 

do \(\left|x-1\right|\ge0\forall x;-2< 0\)

\(2\left(\frac{3}{4}-5x\right)=\frac{4}{5}-3x\Leftrightarrow\frac{3}{2}-10x=\frac{4}{5}-3x\)

\(\Leftrightarrow-7x=\frac{4}{5}-\frac{3}{2}=\frac{8-15}{10}=-\frac{7}{10}\Leftrightarrow x=\frac{1}{10}\)

\(\left(x-5\right)^4-2^2.4=53\Leftrightarrow\left(x-5\right)^4-16=53\)

\(\Leftrightarrow\left(x-5\right)^4=69\Leftrightarrow\left[\left(x-5\right)^2\right]^2=\sqrt{69}^2\)

TH1 : \(\left(x-5\right)^2=\sqrt{69}\Rightarrow x-5=\sqrt{\sqrt{69}}\Rightarrow x=\sqrt{\sqrt{69}}+5=\sqrt[4]{69}+5\)

TH2 : \(\left(x-5\right)^2=-\sqrt{69}\)( vô lí ) 

\(2x^2y.x^3y^2x=2x^5y^3x=2x^6y^3\)bậc 9 

-> chọn D