Step 1 :\(\ln ((x^{2}-2) \cdot 9)=\ln (7)\)
Step 2 :\(\ln (9x^{2}-18)=\ln (7)\)
Step 3 :\(9x^{2}-18=7\)
Step 4 :\(9x^{2}=25\)
Step 5 :\(x^{2}=\frac{25}{9}\)
Step 6 :\(x=\pm \sqrt{\frac{25}{9}}\)
Step 7 :\(x=\pm \frac{5}{3}\)
Step 8 :Check the solutions: For \(x=\frac{5}{3}\), \(x^{2}-2=\left(\frac{5}{3}\right)^{2}-2=\frac{7}{9}\), which is positive. For \(x=-\frac{5}{3}\), \(x^{2}-2=\left(-\frac{5}{3}\right)^{2}-2=\frac{7}{9}\), which is also positive.
Step 9 :\(\boxed{x=\frac{5}{3}, x=-\frac{5}{3}}\)