Question

tìm x biết:

a)3^x+1 = 27 

b)6^x-1 = 36

c)3^2x+1 = 243

d)x^50 = x

Answer 1

đề sai thì phải

Answer 2

\(a,3^{x+1}=27\)

\(3^{x+1}=3^3\)

\(x+1=3\)

\(x=3-1=2\)

\(b,6^{x-1}=36\)

\(6^{x-1}=6^2\)

\(x-1=2\)

\(x=2+1=3\)

\(c,3^{2x+1}=243\)

\(3^{2x+1}=3^5\)

\(2x+1=5\)

\(2x=5+1=6\)

\(x=6:2=3\)

Mình hong hiểu câu d :<

Answer 3

\(x^{50}=x\\ \Rightarrow x^{50}-x=0\\ \Rightarrow x\left(x^{49}-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=0\\x^{49}-1=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=0\\x^{49}=1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)