Ai giúp mình 2 cái bài này với ! Mình đang cần gấp , mình cảm ơn trc nha 😊✌️
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Trời trời giúp mình với mấy thần đồng tiếng anh ơi , mình sắp toang ròi 😢😢😢
1 Sue wishes she hadn't bought that new book
2 Unless you walk faster, you will be late
3 Carol spent 2 hours fixing the television sets
4 I make these handicrafts by myself
5 If I were you, I would take the bus instead of the train
II
1 She doesn't have to get up early on Saturday
2 Children mustn't be left alone in car
3 John must explain this if he want his student to succeed
4 I have to file the report this week
5 We don't have to work overtime on Saturdays
6 You mustn't drive more than 25 mph in this zone
7 She didn't have to attend the presentation yesterday
8 She has to pick up her children at school
9 You don't have to arrive before 8
10 They had to visit the doctor yesterday as they didn't feel well
a: \(=\left(2a^2-3a^2-4a^2\right)+\left(-0.5a-2.5a+3a\right)+\left(5-4+7\right)=-5a^2+8\)
b: \(=\left(a^3-a^3\right)+\left(-2a^2-3a^2+4a^2\right)+\left(a+a-a\right)+\left(-5+4\right)=-a^2+a-1\)
c: \(=-b^4+3b^2-3b-1-b^3+1-3b^2+b^4-5+4b^3+5\)
\(=3b^3-3b\)
Bài 3:
a. \(R=R1+R2=15+30=45\Omega\)
b. \(\left\{{}\begin{matrix}I=U:R=9:45=0,2A\\I=I1=I2=0,2A\left(R1ntR2\right)\end{matrix}\right.\)
c. \(\left\{{}\begin{matrix}U1=R1.I1=15.0,2=3V\\U2=R2.I2=30.0,2=6V\end{matrix}\right.\)
Bài 4:
\(I1=U1:R1=6:3=2A\)
\(\Rightarrow I=I1=I2=2A\left(R1ntR2\right)\)
\(U=R.I=\left(3+15\right).2=36V\)
\(U2=R2.I2=15.2=30V\)
a: Xét tứ giác HNCE có
M là trung điểm của HC
M là trung điểm của NE
Do đó: HNCE là hình bình hành
Hiểu như này:
\(\dfrac{a}{1+a}+\dfrac{b}{1+b}+\dfrac{b}{1+b}=3-\left(\dfrac{1}{1+a}+\dfrac{1}{1+b}+\dfrac{1}{1+b}\right)\le3-\dfrac{9}{1+a+1+b+1+b}=\dfrac{3\left(a+2b\right)}{3+a+2b}\)
1,D
2,B
3,B
4,C
1,D
2,A
3,A
4,D
5,C