( 0,25 )⁴ . 512

\(=\left(\frac{1}{4}\right)^4.2^9\)

\(=\left(\frac{1}{2^2}\right)^4.2^9\)

\(=\frac{1}{\left(2^2\right)^4}.2^9\)

\(=\frac{1}{2^8}.2^9=2\)

giup voi

( 0,25 )⁴ . 512

\(=\left(\frac{1}{4}\right)^4.2^9\)

\(=\left(\frac{1}{2^2}\right)^4.2^9\)

\(=\frac{1}{\left(2^2\right)^4}.2^9\)

\(=\frac{1}{2^8}.2^9=2\)

\(\text{Vì }\hept{\begin{cases}\left|2x-\frac{1}{3}\right|\ge0,∀x\\\left(-y+2\right)^4\ge0,∀y\end{cases}}\Rightarrow A=\left|2x-\frac{1}{3}\right|\left(-y+2\right)^4-1\frac{3}{4}\ge-1\frac{3}{4}=\frac{-7}{4},∀x,y\)

Dấu "=" xảy ra \(\Leftrightarrow\hept{\begin{cases}2x-\frac{1}{3}=0\\-y+2=0\end{cases}}\Leftrightarrow\hept{\begin{cases}2x=\frac{1}{3}\\-y=-2\end{cases}}\Leftrightarrow\hept{\begin{cases}x=\frac{1}{6}\\y=2\end{cases}}\)

1. Have you ever (do) done volunteer work?

2. He (collect) has collected of old books and clothes for street children so far.

3. I (not see) have not seen your brother yet.

4. I (watch) have watched the film Titanic already.

5. Have you (buy) bought the laptop yet?

cảm ơn bạn ^^

TL:

= -3/17 - 2/13 - (-20/17) - 11/13

= -3/17 + 20/17 - ( 2/13 + 11/13)

= 1 - 1 = 0

_HT_