Question

cho em hỏi câu b và c với ạ!

 

Answer 1

b) Để B nguyên thì \(3\sqrt{x}-2⋮2\sqrt{x}+1\)

\(\Leftrightarrow6\sqrt{x}-4⋮2\sqrt{x}+1\)

\(\Leftrightarrow-7⋮2\sqrt{x}+1\)

\(\Leftrightarrow2\sqrt{x}+1\in\left\{1;-1;7;-7\right\}\)

\(\Leftrightarrow2\sqrt{x}\in\left\{0;-2;6;-8\right\}\)

\(\Leftrightarrow\sqrt{x}\in\left\{0;3\right\}\)

hay \(x\in\left\{0;9\right\}\)

c) Để C nguyên thì \(\sqrt{x}-3⋮2\sqrt{x}+1\)

\(\Leftrightarrow2\sqrt{x}-6⋮2\sqrt{x}+1\)

\(\Leftrightarrow-7⋮2\sqrt{x}+1\)

​\(\Leftrightarrow x\in\left\{0;9\right\}\)​