một đoạn ADN chứa hai gen :
- gen thứ nhất dài 5100\(\Lambda\)và có tỷ lệ từng loại nu trên mạch đơn thứ nhất như sau:
G:X:A:T = 1:2:3:4
-gen thứ hai dài bằng nửa chiều dài của gen thứ nhất và số lượng nu từng loại trên mạch đơn thứ hai là : A= T/2= G/3= X/4
xác định:
a/ số lg và tỷ lệ từng loại nu trên mỗi mạch đơn của mỗi gen
b/ số lg từng loại nu của đoạn ADN
help me pleas ...thanks

I/
have you been?
have seen
did you do
have ever visited
bought
have learnt//was
have just cleaned
II/
Minh hasn`t written to his pen pal for five months
i haven`t visited kuala lumpur for 3 years
how long have you studied english?
they have built this house for 2 months
my father has worked in this factory since last week

1 she is a skillful dancer
2 Mr.quyen is really careful typist
3 she dances bellet excellently
4 they work efficiently
5 since i work hard , i was tired
6 how about going to cinema tonight
7 if we don`t recycle ued things , we won`t save natural resources
8 if it litter the place around you , it will be a yunk yar

B1
1 waited
2 wrote
3 opened
4 showed
5 joined
6 were
7 knew
8 were
9 were
10 made
11 didn`t forget
12 didn`t snow
13 were
14 lived

1/ if we keep the enviroment clean , we will live with happier and heathier life
2/ i suggest that you should buy a new compter
3/ if you try your best to do this test , you will get good marks
4/ i suggest that we should collect plastics bag around the scoolyard
5/ i suggest that you should go to school by bus
6/if you don`t work carefully, you will lose yourjob
7/ because it`s too loud , i can`t her you clearly
8/ i suggest that we should do the test quickly

1/ how long ha she left school
2/ that`s best movie i have ever seen
3/ we are interested in book, especially E book
4/ it took their 45 minutes to do the test
5/ she hasn`t worn the dress for her sister`s wedding
(ko bik đúng ko _-_)

1/ the man whom i talked to yesterday is very kind
2/ the hotel which we are living s built twenty years ago
3/ the car which Mr smith is driving looks new
4/ i apologized to the woman whom i spilled coffee
5/ the subject which Dr Wilson spoke about was interesting
6/ i met the woman whose husband is the president of the coporation
7/ yesterday i ran into an old friend whom i haven`t seen for years
8/ Daisy whom you can depend on is trustworthy
9/ i have to call the man whose raincoat i accidentally picked up after the meeting
10/ we used the map which my sister drew for us

1,
P = a + b - ab
\(\Rightarrow P=2+\sqrt{3}+2-\sqrt{3}-\left(2+\sqrt{3}\right).\left(2-\sqrt{3}\right)\)
\(=2+\sqrt{3}+2-\sqrt{3}-4+3\)
\(=3\)
2,
a/ vs \(x>0,x\ne1\)
P = \(\left(\frac{1}{x-\sqrt{x}}+\frac{1}{\sqrt{x}-1}\right)\div\frac{\sqrt{x}}{x-2\sqrt{x}+1}\)
\(=\left(\frac{1}{\sqrt{x}.\left(\sqrt{x}-1\right)}+\frac{\sqrt{x}}{\sqrt{x}.\left(\sqrt{x}-1\right)}\right).\frac{\sqrt{x}-1}{\sqrt{x}}\)
\(=\frac{1+\sqrt{x}}{\sqrt{x}.\left(\sqrt{x}-1\right)}.\frac{\sqrt{x}-1}{\sqrt{x}}\)
\(=\frac{1+\sqrt{x}}{x}\)
b/ để P > \(\frac{1}{2}\) thì \(\frac{1+\sqrt{x}}{x}>\frac{1}{2}\)
\(\Leftrightarrow\frac{1+\sqrt{x}}{x}-\frac{1}{2}>0\)
\(\Leftrightarrow\frac{\left(1+x\right).2}{2x}-\frac{x}{2x}>0 \)
\(\Leftrightarrow\frac{2+2x-x}{2x}>0\)
\(\Leftrightarrow\frac{2+x}{2x}>0\)
mà x >0 \(\Rightarrow\) 2x > 0
\(\Rightarrow2+x>0\)
\(\Leftrightarrow x>-2\)
vậy...

a/ vì bố máu AB nên có KG là l^A l^B
mẹ máu O nên KG là l^o l^o
sơ đồ lai
P ___l^Al^B______x_____l^ol^o_____
G l^A , l^B ___________l^o
F _________ l^Al^O : l^Bl^O_________
\(\Rightarrow\) TLKH ; máu A , máu B