Question

Giải hệ phương trình:

\(\left\{{}\begin{matrix}x+2y=5\sqrt{5}\\\sqrt{5}x+y=5+2\sqrt{5}\end{matrix}\right.\)

Answer 1

sử dụng phương pháp thế:

\(\Leftrightarrow\left\{{}\begin{matrix}x=5\sqrt{5}-2y\\\sqrt{5}\left(5\sqrt{5}-2y\right)+y=5+2\sqrt{5}\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=5\sqrt{5}-2y\\25-2\sqrt{5}y+y=5+2\sqrt{5}\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=5\sqrt{5}-2y\\y=2\sqrt{5}\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=\sqrt{5}\\y=2\sqrt{5}\end{matrix}\right.\)