Question

[Nhóm Winx là mãi mãi [Kazy]]

Tính hợp lý

\(25\left(-\frac{1}{5}\right)^3+\frac{1}{5}-2\left(-\frac{1}{2}\right)^2-\frac{1}{2}\)

Nhanh nha

Answer 1

[Mất nick đau lòng con quốc quốc]

chán thím ghê -,- 

\(25\left(-\frac{1}{5}\right)^3+\frac{1}{5}-2\left(-\frac{1}{2}\right)^2-\frac{1}{2}\)

\(=\)\(\left(25.\frac{\left(-1\right)^3}{5^3}+\frac{1}{5}\right)-\left(2.\frac{\left(-1\right)^2}{2^2}+\frac{1}{2}\right)\)

\(=\)\(\left(25.\frac{-1}{5^3}+\frac{1}{5}\right)-\left(2.\frac{1}{2^2}+\frac{1}{2}\right)\)

\(=\)\(\frac{1}{5}\left(25.\frac{-1}{5^2}+1\right)-\frac{1}{2}\left(2.\frac{1}{2}+1\right)\)

\(=\)\(\frac{1}{5}\left(-1+1\right)-\frac{1}{2}\left(1+1\right)\)

\(=\)\(\frac{1}{5}.0-\frac{1}{2}.2\)

\(=\)\(-1\)