Question

 

Answer 1

\(425:x\) dư 28 \(\Rightarrow397⋮x\)

\(724:x\) dư 32 \(\Rightarrow692⋮x\)

\(692=2^2\cdot173\\ 397=397\\ \RightarrowƯCLN\left(397;692\right)=1\)

\(\Rightarrow x\inƯC\left(692;397\right)=Ư\left(1\right)=\left\{-1;1\right\}\)

Mà \(x\in N\Rightarrow x=1\)