Question

a, \(2^{x-1}\) = 16

b,\(\left(x-1\right)^2\) = 25

Answer 1

Answer 2

\(a,2^{x-1}=16\)

\(\Rightarrow2^{x-1}=2^4\)

\(\Rightarrow x-1=4\) (vì cùng cơ số)

\(\Rightarrow x=4+1\)

\(\Rightarrow x=5\)

Vậy x = 5

\(b,\left(x-1\right)^2=25\)

\(\Rightarrow\left(x-1\right)^2=\left(\pm5\right)^2\)

\(\Rightarrow\left(x-1\right)=\pm5\)

\(\Rightarrow\left[{}\begin{matrix}x-1=5\\x-1=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5+1\\x=-5+1\end{matrix}\right.\Rightarrow}\left[{}\begin{matrix}x=6\\x=-4\end{matrix}\right.\)Vậy x = 6 ; x = -4

Answer 3

a, \(2^{x-1}\) =16

\(\Leftrightarrow2^{x-1}=2^4\)

\(\Leftrightarrow x-1=4\)

\(\Leftrightarrow x=4+1=5\)

Vậy x=5

Answer 4

\(a,2^{x-1}=16\)

\(\Rightarrow2^{x-1}=2^4\)

\(\Rightarrow x-1=4\) (vì cùng cơ số)

\(\Rightarrow x=4+1\)

\(\Rightarrow x=5\)

Vậy x = 5

\(b,\left(x-1\right)^2=25\)

\(\Rightarrow\left(x-1\right)^2=\left(\pm5\right)^2\)

\(\Rightarrow x-1=\pm5\)

\(\Rightarrow\left[{}\begin{matrix}x-1=5\\x-1=-5\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=5+1\\x=-5+1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=6\\x=-4\end{matrix}\right.\)

Vậy x = 6 ; x = -4