\(ĐK:x\ne0;7\)
\(\Rightarrow\dfrac{\left(x-7\right)\left(x-7\right)-3x^2}{x\left(x-7\right)}=\dfrac{49}{x\left(x-7\right)}\)
\(\Leftrightarrow\left(x-7\right)^2-3x^2=49\)
\(\Leftrightarrow x^2-14x+49-3x^2-49=0\)
\(\Leftrightarrow-2x^2-14x=0\)
\(\Leftrightarrow-2x\left(x+7\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\left(ktm\right)\\x=7\left(tm\right)\end{matrix}\right.\)
Vậy \(S=\left\{7\right\}\)
Đúng 0
Bình luận (0)
