Question

Câu  2: Giải  phương trình và hệ phương trình sau:

a) √2x+1=7-x

b)

Answer 1

a) \(\sqrt{2}x+1=7-x\Leftrightarrow\left(\sqrt{2}+1\right)x=6\Leftrightarrow x=\dfrac{6}{\sqrt{2}+1}=-6+6\sqrt{2}\)

b) \(\left\{{}\begin{matrix}2x+3y=2\\x-y=\dfrac{1}{6}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x+3y=2\\3x-3y=\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}5x=\dfrac{5}{2}\\x-y=\dfrac{1}{6}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{1}{2}\\y=x-\dfrac{1}{6}\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}x=\dfrac{1}{2}\\y=\dfrac{1}{3}\end{matrix}\right.\)

Answer 2

b)