Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\sqrt{81}=9\)
\(\sqrt{0}=0\)
\(\sqrt{9}=3\)
Học tốt!!!
1. Mrs. Nga usually......watches.........................(watch) TV after dinner.
2. Where ........is.......................(be) Tom?
He...........is doing.................(do) his homework in his room.
3. In England the sun ..........doesn't.....shine..............................(not shine) every day.
4. You should.......help......................(help) old people.
5. There .........(be) two bedrooms in my house.
1. Mrs. Nga usually.....watches..........................(watch) TV after dinner.
2. Where ..........does.....................(be) Tom?
He.....................does.......(do) his homework in his room.
3. In England the sun ......doesn't..shine...............(not shine) every day.
4. You should.....help........................(help) old people.
5. There ..are.......(be) two bedrooms in my house.
Bài 1:
a)\(\frac{2}{3}.\frac{5}{2}-\frac{3}{4}.\frac{2}{3}=\frac{5}{3}-\frac{1}{2}=\frac{7}{6}\)
b)\(2.\left(\frac{-3}{2}\right)^2-\frac{7}{2}=\frac{2.9}{4}-\frac{7}{2}=\frac{9-7}{2}=\frac{2}{2}=1\)
c)\(-\frac{3}{4}.\frac{68}{13}-0,75.\frac{36}{13}=\frac{-3.4.17}{4.13}-\frac{3.9.4}{4.13}=\frac{-51-27}{13}=\frac{-78}{13}=-6\)
Bài 2:
a)|x-1,4|=1,6
\(\Rightarrow\left[\begin{array}{nghiempt}x-1,4=1,6\\x-1,4=-1,6\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=3\\x=-0,2\end{array}\right.\)
b) \(\frac{3}{4}-x=\frac{4}{5}\)
\(x=\frac{3}{4}-\frac{4}{5}=-\frac{1}{20}\)
c)(1-2x)3=-8
(1-2x)3=(-2)3
1-2x=-2
2x=3
x=\(\frac{3}{2}\)
Bài 3:
\(\frac{x}{2}=\frac{y}{5}=\frac{z}{7}=k\)
\(\Rightarrow\begin{cases}x=2k\\y=5k\\z=7k\end{cases}\)
A=\(\frac{2k-5k+7k}{2k+2.5k-7k}=\frac{4k}{5k}=\frac{4}{5}\)
=> x=4/5 . 2= 8/5
y=4/5 . 5=4
z=4/5.7=28/5




thank nhá
oke nhé
tặng cho vài punch
cảm ơn bạn nha
ok hóa tôi đúp r
ok
ờm