Question

CẦN GIÚP VS Ạ. KHÓ QUÁ ( TRƯỚC CHIỀU T3/24/10 NHÉ Ạ)

Answer 1

a: gọi d=ƯCLN(n+4;n+5)

=>\(\left\{{}\begin{matrix}n+5⋮d\\n+4⋮d\end{matrix}\right.\)

=>\(n+5-n-4⋮d\)

=>\(1⋮d\)

=>d=1

b: gọi d=ƯCLN(2n+3;2n+1)

=>\(\left\{{}\begin{matrix}2n+3⋮d\\2n+1⋮d\end{matrix}\right.\)

=>\(2n+3-2n-1⋮d\)

=>\(2⋮d\)

mà 2n+3 lẻ

nên d=1