Question

Tính hợp lí nếu co thể :

25(-1/5) ³ + 1/5 - 2 (-1/2)² - 1/2

Answer 1

25*(-1/5)^3+ 1/5 - 2*(-1/2)^2- 1/2

=(-1/5)+(1/2-1/2)

=(-1/5)+0

=-1/5

Chắc z

Answer 2

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

\(=\dfrac{1}{5}\left(-25\cdot\dfrac{1}{25}+1\right)-\dfrac{1}{2}\left(-2\cdot\dfrac{1}{2}+1\right)\)

\(=\dfrac{1}{5}\cdot0-\dfrac{1}{2}\cdot0=0\)