a, \(75\) . \(20,9\) \(+\) \(5²\) . \(20,9\)
\(=\) \((75 + 5²)\) . \(20,9\)
\(=\) \(100\) . \(20,9\)
\(=\) \(2090\)
b, \(-8\) . \(40\) \(+\) \(2\) . \(108\) \(+\) \(24\)
\(=\) \(-8\) . \(8\) .\(5\) \(+\) \(8\) . \( 27\) + \(8\) . \(3\)
\(=\) \(-8\) . \((40 - 27 - 3)\)
\(=\) \(-8\) . \(10\)
\(=\) \(-80\)
c, \(86\) . \(15\) \(+\) \(150\) . \(1,4\)
\(=\) \(86\) . \(15\) \(+\) \(5\) . \(10\) . \(1,4\)
\(=\) \(86\) . \(15\) \(+\) \(5\) . \(14\)
\(=\) \(15\) . \((86 + 14)\)
\(=\) \(15\) . \(100\)
\(=\) \(1500\)