Answer:
[tex]x = 64 \\ \\ x(x - 8) \\ = 64(64 - 8) \\ = 64 - 56 \\ = 8[/tex]
Hope it helps!
[tex]\sf \: x = 64 \\ \\ \sf Substitute \: 64 \: in \: the \: place \: in \: 'x'\\ \\ \sf \: x(x -8) \\ \sf \: = 64(64 - 8) \\ \sf \: = 64 \times (56) \\ \sf = 64 \times 56 \\ = \boxed{ \bf 3584}[/tex]