Question

Tìm số tự nhiên x biết rằng:112 chia hết cho x;140 chia hết cho x, 1<x<25

Answer 1

\(112⋮x;140⋮x\Rightarrow x\inƯC\left(112,140\right);1< x< 25\\ 112=2^4\cdot7;140=2^2\cdot5\cdot7\\ ƯCLN\left(112,140\right)=2^2\cdot7=28\\ ƯC\left(112,140\right)=Ư\left(28\right)=\left\{1;4;7;28\right\}\\ \Rightarrow x\in\left\{4;7\right\}\)