Giúp mk với!!! Mk sắp đi học rùi!!!

k mình đi rồi mình trả lời

a: =>|x-1|=4-2x

\(\Leftrightarrow\left\{{}\begin{matrix}x< =2\\\left(4-2x-x+1\right)\left(4-2x+x-1\right)=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< =2\\\left(-3x+5\right)\left(3-x\right)=0\end{matrix}\right.\)

hay x=5/3

b: \(\Leftrightarrow2^x\cdot\dfrac{9}{2}=9\cdot2^5\)

\(\Leftrightarrow2^x=64\)

hay x=6

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

\(\Leftrightarrow2^x\left(\frac{1}{2}+4\right)=9.2^5\)

\(\Leftrightarrow2^x\frac{9}{2}=9.2^5\)

\(\Leftrightarrow2^x\frac{9}{2}=288\)

\(\Leftrightarrow2^x=64\)

\(\Leftrightarrow2^x=2^6\)

\(\Rightarrow x=6\)

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

<=> \(2^x\left(\frac{1}{2}+4\right)=9.2^5\)

<=> \(2^x.\frac{9}{2}=9.2^5\)

<=> \(2^x=2^6\)

<=> x = 6

2^x.(1/2+4)=9.2^5

2^x.9/2=9.2^5

2^x.9/2=9.32

2^x.9/2=288

2^x=288:9/2

2^x=288.2/9

2^x=64

2^x=2^6

vậy x=6

\(\dfrac{1}{2}\cdot2^n+4\cdot2^n=9\cdot2^5\\ \Rightarrow2^n\left(\dfrac{1}{2}+4\right)=9\cdot2^5\\ \Rightarrow2^n\cdot\dfrac{9}{2}=9\cdot2^5\\ \Rightarrow2^{n-1}\cdot9=9\cdot2^5\\ \Rightarrow n-1=5\\ \Rightarrow n=6\)

b) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)

\(\Rightarrow\left(x+\frac{1}{2}\right)^2=\left(\pm\frac{1}{4}\right)^2\)

\(\Rightarrow x+\frac{1}{2}=\pm\frac{1}{4}.\)

\(\Rightarrow\left[{}\begin{matrix}x+\frac{1}{2}=\frac{1}{4}\\x+\frac{1}{2}=-\frac{1}{4}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{1}{4}-\frac{1}{2}\\x=\left(-\frac{1}{4}\right)-\frac{1}{2}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-\frac{1}{4}\\x=-\frac{3}{4}\end{matrix}\right.\)

Vậy \(x\in\left\{-\frac{1}{4};-\frac{3}{4}\right\}.\)

c) \(\left(3x+2\right)^3=-27\)

\(\Rightarrow\left(3x+2\right)^3=\left(-3\right)^3\)

\(\Rightarrow3x+2=-3\)

\(\Rightarrow3x=\left(-3\right)-2\)

\(\Rightarrow3x=-5\)

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

\(\Rightarrow x=-\frac{5}{3}\)

Vậy \(x=-\frac{5}{3}.\)

Chúc bạn học tốt!

Bạn ơi, gõ Công thức trực quan cho dễ nhìn đi bạn! :)

a) \(x:\left(-\frac{1}{3}\right)^3=-\frac{1}{3}\)

\(\Rightarrow x=\left(-\frac{1}{3}\right).\left(-\frac{1}{3}\right)^3\)

\(\Rightarrow x=\left(-\frac{1}{3}\right)^4\)

\(\Rightarrow x=\frac{1}{81}\)

Vậy \(x=\frac{1}{81}.\)

d) \(27^x:3^x=9\)

\(\Rightarrow\left(27:3\right)^x=9\)

\(\Rightarrow9^x=9\)

\(\Rightarrow9^x=9^1\)

\(\Rightarrow x=1\)

Vậy \(x=1.\)

e) \(\frac{16}{2^x}=2\)

\(\Rightarrow2^x=16:2\)

\(\Rightarrow2^x=8\)

\(\Rightarrow2^x=2^3\)

\(\Rightarrow x=3\)

Vậy \(x=3.\)

Chúc bạn học tốt!

a: \(3^n\cdot3^4\cdot\dfrac{1}{9}=3^7\)

\(\Leftrightarrow3^n\cdot3^2=3^7\)

=>n+2=7

hay n=5

b: \(\Leftrightarrow2^n\cdot\left(\dfrac{1}{2}+4\right)=9\cdot2^5\)

\(\Leftrightarrow2^n=9\cdot2^5:\dfrac{9}{2}=9\cdot\dfrac{2}{9}\cdot2^5=2^6\)

hay n=6