Use Rule of Zero: \({x}^{0}=1\).
\(21\times 1-5\times {2}^{2}-4\times {2}^{-1}+{5}^{0}\)
Simplify \({2}^{2}\) to \(4\).
\(21\times 1-5\times 4-4\times {2}^{-1}+{5}^{0}\)
Use Negative Power Rule: \({x}^{-a}=\frac{1}{{x}^{a}}\).
\(21\times 1-5\times 4-4\times \frac{1}{2}+{5}^{0}\)
\(21-5\times 4-4\times \frac{1}{2}+{5}^{0}\)
Simplify \(5\times 4\) to \(20\).
\(21-20-4\times \frac{1}{2}+{5}^{0}\)
Simplify \(4\times \frac{1}{2}\) to \(\frac{4}{2}\).
\(21-20-\frac{4}{2}+{5}^{0}\)
Simplify \(\frac{4}{2}\) to \(2\).
-22+[21+5^0]
