Giúp mình 2 bài này với. Mình cảm ơn.
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\dfrac{4}{7}+\dfrac{2}{9}+\dfrac{1}{4}+\dfrac{3}{7}+\dfrac{7}{9}+\dfrac{75}{100}\\ =\dfrac{4}{7}+\dfrac{2}{9}+\dfrac{1}{4}+\dfrac{3}{7}+\dfrac{7}{9}+\dfrac{3}{4}\\ =\left(\dfrac{4}{7}+\dfrac{3}{7}\right)+\left(\dfrac{2}{9}+\dfrac{7}{9}\right)+\left(\dfrac{1}{4}+\dfrac{3}{4}\right)\\ =\dfrac{7}{7}+\dfrac{9}{9}+\dfrac{4}{4}\\ =1+1+1\\ =3\)
Ta có: \(\dfrac{7}{11}=\dfrac{7\times3}{11\times3}=\dfrac{21}{33};\dfrac{8}{11}=\dfrac{8\times3}{11\times3}=\dfrac{24}{33}\)
2 phân số giữa là: \(\dfrac{22}{33};\dfrac{23}{33}\)
\(=\left(\dfrac{4}{7}+\dfrac{3}{7}\right)+\left(\dfrac{2}{9}+\dfrac{7}{9}\right)+\left(\dfrac{1}{4}+\dfrac{3}{4}\right)=1+1+1=3\)
1 There are 5000 living languages in the world
2 It is Chinese
3 It is English
4 Yes, because I think English is interesting
V
1 He used to play the guitar at night
2 She wishes she had a pen pal
3 We started learning E 4 years ago
4 How long have you had that car
1 Nam said that he came from Thanh Hoa city
2 Mr Cuong asked me if I liked pop music
3 Although the weather was bad, we visited Bat Trang village
4 Because it was raining, they cancelled the trip to Trang An
5 We have to try harder so that our handicrafts can keep up with theirs
6 She grew up in Thanh Hoa city
II
1 Eventhough it was very cold out, we decided to go for a walk
2 Mai studied hard for the exam so that she could have good marks
1. nam said that he came from Thanh Hoa city.
2.Mr. Cuong asked if I liked pop music
3. although the weather was bad, we visited bat Trang village
Bài 2:
a: =>168x+20=6x-21
=>162x=-41
hay x=-41/162
b: \(\Leftrightarrow2\left(3x-8\right)=3\left(5-x\right)\)
=>6x-16=15-3x
=>9x=31
hay x=31/9
c: \(\Leftrightarrow4\left(x^2+8x-20\right)-\left(x+4\right)\left(x+10\right)=3\left(x^2+2x-8\right)\)
\(\Leftrightarrow4x^2+32x-80-x^2-14x-40-3x^2-6x+24=0\)
=>12x-96=0
hay x=8
Đặt\(\begin{cases} x+y=S \\ xy=P \end{cases}\)
Ta có:\(\begin{cases} S-2P=0 \\ S-P^2=\sqrt{(P-1)^2+1} \end{cases}\)
\(\Leftrightarrow\)\(\begin{cases} S=2P \\ 2P-P^2=\sqrt{(P-1)^2+1} \end{cases}\)
\(\Leftrightarrow\)\(\begin{cases} S=2P \\ (2P-P^2)^2=(P-1)^2+1 \end{cases}\)
\(\Leftrightarrow\)\(\begin{cases} S=2P \\ 4P^2-4P^3+P^4=P^2-2P+2 \end{cases}\)
\(\Leftrightarrow\)\(\begin{cases} S=2P \\ P^4-4P^3+3P^2+2P-2=0 \end{cases}\)
\(\Leftrightarrow\)\(\begin{cases} S =2+2\sqrt{3}\\ P=1+\sqrt{3} \end{cases}\)(1)hoặc\(\begin{cases} S=2 \\ P=1 \end{cases}\)(2)hoặc\(\begin{cases} S=2-2 \sqrt{3}\\ P=1-\sqrt{3} \end{cases}\)(3)
Còn lại là thay vào biểu thức x2-Sx+P=0 thôi
I
1 will have
2 would have
3 have
4 had
5 will make
6 would make
7 has
8 had
9 is
10 were
II
1 have
2 had
3 had had
4 will go
5 would go
6 would have gone
7 is
8 were - would visit
9 had been - would have visited
10 wouldn't be - were
I.
1. will have
2. would have
3. have
4. had
5. will made
6. would made
7. has
8. had
9. is
10. were
II.
1. have
2. had
3. had had
4. will go
5. would go
6. would have gone
7. is
8. were - would visit
9. had been - would have visited
10. will not be - is