0};} \right. \left \{ {x^{2}-8x-9=0,} \atop {8x>-9;}} \right. \left \{ {{\left \{ {{x_1=9}, \atop {x_2=-1,}} \right.} \atop {x>-1, 125}} \right. " alt=" log_x^{2} (8x+9)=log_x^{2} x^{2} \\ \left \{ {8x+9=x^{2},} \atop {8x+9> 0};} \right. \left \{ {x^{2}-8x-9=0,} \atop {8x>-9;}} \right. \left \{ {{\left \{ {{x_1=9}, \atop {x_2=-1,}} \right.} \atop {x>-1, 125}} \right. " align="absmiddle" class="latex-formula">
Ответ: -1+9=8