\(x^2-7x+8=2\sqrt{x}\)
\(\Leftrightarrow\left(x^2-6x+9\right)-x-1=2\sqrt{x}\)
\(\Leftrightarrow\left(x-3\right)^2=x+2\sqrt{x}+1=\left(\sqrt{x}+1\right)^2\)
\(\Leftrightarrow\left(x-3\right)^2-\left(\sqrt{x}+1\right)^2=0\)
\(\Leftrightarrow\left(x-\sqrt{x}-4\right)\left(x+\sqrt{x}-2\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-\sqrt{x}-4=0\left(1\right)\\x+\sqrt{x}-2=0\left(2\right)\end{cases}}\)
Giải (1): Ta đc: x= (9+căn17)/2
Giải (2) ta đc: x=1
Đúng 0
Bình luận (0)
