kết quả bằng :36*x^2

\(A=-x^2+2xy-4y^2+x-10y-8\)

=> \(-4A=4x^2-8xy+16y^2-4x+40y+32\)

                \(=\left(4x^2-8xy+4y^2\right)-\left(4x-4y\right)+1+12y^2+36y+31\)

                  \(=\left(2x-2y\right)^2-2\left(2x-2y\right)+1+3\left(4y^2+2.2y.3+9\right)+4\)

                   \(=\left(2x-2y+1\right)^2+3\left(2y+3\right)^2+4\ge4\)

=> \(A\le4:-4=-1\)

"=" xảy ra <=> \(\hept{\begin{cases}2x-2y+1=0\\2y+3=0\end{cases}\Leftrightarrow}\hept{\begin{cases}y=-\frac{3}{2}\\x=2\end{cases}}\)

Vậy max A=-1 <=> x=2 y=-3/2

Câu b em làm tương tự nhé!

dài thế sao làm đc

Trường bn gắt quá

câu a ) a*x^19+1 

câu b ) 

đa thức chia có bậc 2 nên đa thức dư có bậc không quá 1. vậy đa thức dư có bậc nhất dạng ax+b

Ta có: x67+x47+x27+x7+x+1=(x2−1).Q(x)+ax+bx67+x47+x27+x7+x+1=(x2−1).Q(x)+ax+b

Cho x=1 rồi x=-1 ta được: \hept{1+1+1+1+1+1=a+b−1−1−1−1−1+1=−a+b\hept{1+1+1+1+1+1=a+b−1−1−1−1−1+1=−a+b

⇔\hept{a+b=6−a+b=−4⇔\hept{a=5b=1⇔\hept{a+b=6−a+b=−4⇔\hept{a=5b=1

Vậy dư trong phép chia trên là 5x+1

1 Life in the country is not as good as life in the city

2 These room are cleaned every evening

3 Would you mind decorating the christmas tree

4 It's the first time I have talked to the headmaster

V

1 have ever met

2 worked

3 reading

4 are looking - seeing

5 was

VI

1A

2A

3D

4D

5B

IV/

1. is not as good as life in the city

2. are cleaned every evening

3. decorating the Christmas tree?

4. the first time I have (ever) talked to the headmaster

V/

1. have ever met

2. worked

3. reading

4. are looking - seeing

5. was

VI/

1a 2a 3d 4d 5b

B -> IS GOING
D -> DIDN'T THEY
B -> COULD GO
A -> HASN'T WORN
The national language of China is Chinese
Sari is the traditional dress of India women
beautiful
successful
preparations