8.16. Өрнектердің мәнін табыңдар: 1) \(21^0-3^{-2}-4^{-2}\); 2) \(2^{-3}+3^{-1}+(-4)^2\); 3) \(9^{-1}-\frac{(-3)^2}{(-5)^2}\).

1. \(21^0=1\), \(3^{-2}=\frac19\), \(4^{-2}=\frac1{16}\):

   \(1-\frac19-\frac1{16}=1-\frac{16}{144}-\frac9{144}=\frac{119}{144}\).

2. \(2^{-3}=\frac18\), \(3^{-1}=\frac13\), \((-4)^2=16\):

   \(\frac18+\frac13+16=\frac3{24}+\frac8{24}+\frac{384}{24}=\frac{395}{24}\).

3. \(9^{-1}=\frac19\), ал \(\frac{(-3)^2}{(-5)^2}=\frac9{25}\):

   \(\frac19-\frac9{25}=\frac{25-81}{225}=-\frac{56}{225}\).

Жауабы: 1) \(\frac{119}{144}\); 2) \(\frac{395}{24}\); 3) \(-\frac{56}{225}\).