6. B
7. D
8. C
9. A
10. A
11. A
12. A
13. A
14. B
15. C
16. B
17. C
18. A
19. C
 

Lỗi r

Đoạn AB: nước nóng lên.

Đoạn BC: nước sôi.

Đoạn CD: nước nguội đi.

a: Xét (O) có 

ΔABC nội tiếp đường tròn

AB là đường kính

Do đó: ΔABC vuông tại C

8 Her telephone number isn't known by me

9 The children will be brought home by my students

10 đúng r

11 We were given more information by her

12 All the workers of the plan were being instructed by the chief engineer

Her telephone number isn't known by me

The children will be brought home by my students

A present will be sent to me last week

we were gave more information by her

all the workers of the plan were being instrcued by the chief engineer

8. Her telephone number isn't know by me.

9. The children will be brought home by my students.

10. A present was sent me last week by them.

11. We were given more information by her.

12. All the workers of the plan were being instructed by the chief engineer.

mik gửi cho  bạn 4 mẫu rui đấy

b: 

=>x(y-3)+3(y-3)=17

=>(y-3)(x+3)=17

\(\Leftrightarrow\left(x+3,y-3\right)\in\left\{\left(1;17\right);\left(17;1\right);\left(-1;-17\right);\left(-17;-1\right)\right\}\)

hay \(\left(x,y\right)\in\left\{\left(-2;20\right);\left(14;4\right);\left(-4;-14\right);\left(-20;2\right)\right\}\)

a: =>x(2y+3)+2(2y+3)=5

=>(2y+3)(x+2)=5

\(\Leftrightarrow\left(2y+3;x+2\right)\in\left\{\left(1;5\right);\left(-1;-5\right);\left(5;1\right);\left(-5;-1\right)\right\}\)

hay \(\left(y,x\right)\in\left\{\left(-1;3\right);\left(-2;-7\right);\left(1;-1\right);\left(-4;-3\right)\right\}\)