A=8,14

a, nếu y=0 thì x=(1;4;7) , nếu y=5 thì x=(2;5;8)

b, chưa hiểu đầu bài

c, các cặp x, y lần lượt là (2;0) , (5;3), (8;6)

d, x=4 ,y=1

A\B = (- ∞; -2)

\(\frac{7x+2}{5x+7}=\frac{7x-1}{5x+1}=\frac{7x+2-\left(7x-1\right)}{5x+7-\left(5x+1\right)}=\frac{7x+2-7x+1}{5x+7-5x-1}=\frac{3}{6}=\frac{1}{2}\)

tu \(\frac{7x+2}{5x+7}=\frac{1}{2}=>\left(7x+2\right).2=5x+7=>14x+4=5x+7=>14x-5x=7-4=>9x=3=>x=\frac{3}{9}=\frac{1}{3}\)

vay x=1/3

tick nha

giả sử n^2+4n+2 chia hết cho 4 mà n không chia hết cho 4

=> n chia cho 4 dư a (0<a<4)

=>n=4k+a

=> n^2+4n+2= 16k^2 +8ka +a^2 +16k+4a +2

=>a^2+2 chia hết cho 4, mà 0<a<4 (vô lý do k số nào thỏa mãn)

=> giả thiết sai

vậy nếu n^2 +4n+2 chia hết cho 4 thì n chia hết cho 4

1. I was given a new pair of jeans by my sister on my fifteenth birthday.

2. A supermarket is being built on our street.

3. The animal is fed twice a day .

4. Their car has been sold to pay their debt.

5. Flowers are being grown in front of the garden.

Có mấy chỗ bạn chép sai nhá

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