x + 2xy - 2y = 5
chuminaaa(who is the fastest and best can have a tick)
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Thay x=1 vào pt, ta có: \(\left(a+1\right)\left(b+1\right)\left(c+1\right)=-5\left(1\right)\)
vì vai trò của a,b,c là như nhau, giả sử:\(a>b>c\Rightarrow a+1>b+1>c+1\left(2\right)\)
vì a,b,c là số nguyên nên a+1,b+1,c+1 cũng là số nguyên (3)
từ (1),(2),(3)\(\Rightarrow\hept{\begin{cases}a+1=5\\b+1=1\\c+1=-1\end{cases}\Leftrightarrow\hept{\begin{cases}a=4\\b=0\\c=-2\end{cases}}}\)
81. This is the fastest way to get to the city center.
=> There …is no faster way to get to the city center than this………………………...............…………..................................................
82. If anyone succeeds in solving the problems, it will probably be him.
=> He is the most …………successful man in solving the problems ................………….............................................….........
83. We arrived too late to see the first film.
=> We didn’t ………arrive early enough to see the frist film…................………….............................................….................
84. “Would you mind not smoking in here?”
=> I’d rather ……you didn't smoke in here................………….............................................…........................
85. He wrote the letter in two hours.
=> It took …….him 2 hours to write the letter...............…………............................................…..............................
1. This is the fastest way to get to the city center. There ……… is no faster way than this to get to the city center.……….........……….....................……
2. If anyone succeeds in solving the problems, it will probably be him. He is the most …likely person to succeed in solving the problems.……….
3. We arrived too late to see the first film. We didn’t ……arrive early enough to see the first film.……................……...……..........
4. “Would you mind not smoking in here?” I’d rather ……....you didn’t smoke in here..............……...................
5. He wrote the letter in two hours. It took …… him 2 hours to write the letter.....................……........................
6. “Why don’t we go out for a walk?”--My father suggested ……..going out for a walk............................
7. In spite of his age, Mr. Benson runs 8 miles before breakfast. Though ……..he is old, Mr. Benson runs 8 miles before breakfast.....................
10. These bookshelves are my own work. I made ……..these bookshelves by myself ..............…..............……...................
1. This is the fastest way to get to the city center.
=> There’s no faster way than this to get to the city center.
2. If anyone succeeds in solving the problems, it will probably be him.
=> He is the most likely person to succeed in solving the problems.
3. We arrived too late to see the first film.
=> We didn’t arrive early enough to see the first film.
4. “Would you mind not smoking in here?”
=> I’d rather you didn’t smoke in here.
5. He wrote the letter in two hours.
=> It took him 2 hours to write the letter.
6.“Why don’t we go out for a walk?”
=> My father suggested we should go out for a walk.
7.In spite of his age, Mr. Benson runs 8 miles before breakfast.
=> Though Mr.Benson is old, he runs 8 miles before breakfast.
10.These bookshelves are my own work.
=> I made these bookshelves myself.
A=(x+y+1)(x+y+1)+4
A=(x+y+1)2+4
Vậy MinA=4 khi.......... của @Nguyễn Huy Thắng đó mà ghi tiếp
ngu Anh nhưng ko sao dịch dc chữ Find the minimum = tìm GTNN :)
Bài này không khó cách làm thế này:
x2+y2+2x+2y+2xy+5 = (x2 + y2 +1 +2x + 2y+ 2xy)+4
= (x + y +1 )2 +4
Ta có ( x + y +1)2 >= 0 \(\Rightarrow\) ( x +y +1)2 +4 >= 4
Dấu "=" xảy ra khi và chỉ khi x=y=-0,5
Vậy Min(x+y+1)2 = 4 khi và chỉ khi x=y=-0,5.
Xong rồi đó. Có gì sai sót các bạn góp ý nhé.
Bạn lưu ý, khi đăng đề thì đăng đầy đủ đề (bao gồm cả điều kiện và yêu cầu).
Đề yêu cầu tìm $x,y$?
$x,y$ là số như thế nào? Số nguyên? Số tự nhiên?
Bạn nên ghi rõ ra để mọi người hỗ trợ nhanh hơn nhé.
\(x+2xy-2y=5\)
\(x+2y\times\left(x-1\right)=5\)
\(\left(x-1\right)+2y\times\left(x-1\right)=5-1\)
\(\left(x-1\right)\times\left(2y+1\right)=4\)
Ta có: 4 = (-1) x (-4) = (-2) x (-2) = 2 x 2 = 1 x 4
Ta lập bảng:
⇒ (x; y) ϵ {(5; 0); (-3; -1)}