a. x25 = x0
<=> x25 = 1
<=> x = 1
b. x28 = x5
<=> x28 : x5 = x5 : x5
<=> x23 = 1
<=> x = 1
c. x64 = x
<=> x64 : x = x : x
<=> x63 = 1
<=> x = 1
a) \(x^{25}=x^0\)
⇒\(x^{25}=1\)
⇒\(x^{25}=1^{25}\)
⇒\(x=1\)
b) \(x^{28}=x^5\)
\(x^{28}-x^5=0\)
\(x^5\left(x^{23}-1\right)=0\)
⇔\(\left[{}\begin{matrix}x^5=0\\x^{23}-1=0\end{matrix}\right.\)
⇔\(\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
c) \(x^{64}=x\)
\(x^{64}-x=0\)
\(x\left(x^{63}-1\right)=0\)
⇔\(\left[{}\begin{matrix}x=0\\x^{63}-1=0\end{matrix}\right.\)
⇔\(\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)