Ответ:
\(57_8 = 5 \cdot 8 + 7 = 47_{10}\).
\(715_8 = 7 \cdot 8^2 + 1 \cdot 8 + 5 = 448 + 8 + 5 = 461_{10}\).
\(2020_8 = 2 \cdot 8^3 + 0 \cdot 8^2 + 2 \cdot 8 + 0 = 1024 + 16 = 1040_{10}\).
Ответ: 57₈ = 47₁₀; 715₈ = 461₁₀; 2020₈ = 1040₁₀.
\(57_8 = 5 \cdot 8 + 7 = 47_{10}\).
\(715_8 = 7 \cdot 8^2 + 1 \cdot 8 + 5 = 448 + 8 + 5 = 461_{10}\).
\(2020_8 = 2 \cdot 8^3 + 0 \cdot 8^2 + 2 \cdot 8 + 0 = 1024 + 16 = 1040_{10}\).
Ответ: 57₈ = 47₁₀; 715₈ = 461₁₀; 2020₈ = 1040₁₀.