[tex](81x^{2}-49)(2x^{2}-104x) = 0\\\\(9x + 7)(9x - 7)\cdot2x\cdot(x-52) = 0 \ \ /:2\\\\x(9x+7)(9x-7)(x-52) = 0\\\\x = 0 \ \vee \ 9x +7 = 0 \ \vee \ 9x-7 = 0 \ \vee \ x-52 = 0\\\\x = 0 \ \vee 9x = -7 \ \vee9x = 7 \ x = 52\\\\x = 0 \ \vee \ x = -\frac{7}{9} \ \vee \ x = \frac{7}{9} \ \vee \ x = 52\\\\x \in \{-\frac{7}{9}, 0,\frac{7}{9},52\}[/tex]
