求解 |kx+2|=7-4/x

$$| k x + 2 | = 7 - \frac { 4 } { x }$$

求解 k 的值

$$k=-\frac{9x-4}{x^{2}}$$

$$k=\frac{5x-4}{x^{2}}\text{, }x<0\text{ or }x\geq \frac{4}{7}$$

求解 x 的值

$$\left\{\begin{matrix}x=\frac{-\sqrt{25-16k}+5}{2k}\text{, }&k\leq \frac{25}{16}\text{ and }k\geq -\frac{7}{2}\text{ and }k\neq 0\\x=-\frac{-\sqrt{16k+81}+9}{2k}\text{, }&k\geq -\frac{81}{16}\text{ and }k\leq -\frac{7}{2}\\x=-\frac{\sqrt{16k+81}+9}{2k}\text{, }&k\neq 0\text{ and }k\geq -\frac{81}{16}\\x=\frac{\sqrt{25-16k}+5}{2k}\text{, }&k\neq 0\text{ and }k\leq \frac{25}{16}\\x=\frac{4}{5}\text{, }&k=0\end{matrix}\right.$$