\(\boxed{5}\,\boxed{,}\,\boxed{1}\,\boxed{2}\,\boxed{\stackrel{+}{-}}\,\boxed{x^2}\,\boxed{\div}\,\boxed{4}\,\boxed{\stackrel+-}\,\boxed{=}\to-6,5536\)
\(\boxed{-}\,\boxed{2}\,\boxed{\cdot}\,\boxed{5}\,\boxed{,}\,\boxed{1}\,\boxed{2}\,\boxed{\stackrel+-}\,\boxed{=}\to3,6864\)
\(\boxed{+}\,\boxed{6}\,\boxed{=}\to9,6864\)