Question

[Hoàng Thúy An]

a, 4n - 7 \(⋮\) 5n + 3

b, 11n - 7 \(⋮\) 2n - 3

giúp mình nhé

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(\Leftrightarrow5\left(4n-7\right)⋮5n+3\)

\(\Leftrightarrow20n-35⋮5n+3\)

\(\Leftrightarrow20n+12-47⋮5n+3\)

\(\Leftrightarrow5n+3\in\left\{1;-1;47;-47\right\}\)

hay \(n\in\left\{-\dfrac{2}{5};-\dfrac{4}{5};\dfrac{44}{5};-10\right\}\)

b: \(\Leftrightarrow22n-14⋮2n-3\)

\(\Leftrightarrow22n-33+19⋮2n-3\)

\(\Leftrightarrow2n-3\in\left\{1;-1;19;-19\right\}\)

hay \(n\in\left\{2;1;11;-8\right\}\)