khó quá mik làm ko đc

hay nha bn

con tàu

để đi sang bên kia đường

cảm ơn bạn đã nhắc nhở nhé kẻ mạo danh

hay quá bạn

x−21​=y+43​=z−65​=kvaˋx+y+z=15.

Đặt:

\(x - \frac{1}{2} = y + \frac{3}{4} = z - \frac{5}{6} = k .\)

Bước 1: Viết lại các ẩn theo \(k\):

\({.x=k+\frac{1}{2}y=k-\frac{3}{4}z=k+\frac{5}{6}}\)

Bước 2: Thay vào điều kiện \(x + y + z = 15\):

\(\left(\right. k + \frac{1}{2} \left.\right) + \left(\right. k - \frac{3}{4} \left.\right) + \left(\right. k + \frac{5}{6} \left.\right) = 15.\)

Gom các hệ số:

\(3 k + \left(\right. \frac{1}{2} - \frac{3}{4} + \frac{5}{6} \left.\right) = 15.\)

Bước 3: Quy đồng mẫu để tính hằng số:

Mẫu chung là 12:

\(\frac{1}{2} = \frac{6}{12} , - \frac{3}{4} = - \frac{9}{12} , \frac{5}{6} = \frac{10}{12} .\)

Vậy:

\(6 - 9 + 10 = 7. \Rightarrow 3 k + \frac{7}{12} = 15.\)

Bước 4: Giải \(k\):

\(3 k = 15 - \frac{7}{12} = \frac{180}{12} - \frac{7}{12} = \frac{173}{12} \Rightarrow k = \frac{173}{36} .\)

Bước 5: Tìm \(x , y , z\):

\(x = \frac{173}{36} + \frac{1}{2} = \frac{173}{36} + \frac{18}{36} = \frac{191}{36} , y = \frac{173}{36} - \frac{27}{36} = \frac{146}{36} = \frac{73}{18} , z = \frac{173}{36} + \frac{5}{6} = \frac{173}{36} + \frac{30}{36} = \frac{203}{36} .\)

✅ Vậy nghiệm là:

\(\boxed{x = \frac{191}{36}} , \boxed{y = \frac{73}{18}} , \boxed{z = \frac{203}{36}} .\)

xấp xỉ 9.994 nha bạn

Đây là câu hỏi YES/NO cho các câu đã cho:

1. She is cooking dinner in the kitchen.
   → Is she cooking dinner in the kitchen?
2. They are watching TV now.
   → Are they watching TV now?
3. I am reading a comic book.
   → Am I reading a comic book?
4. He is playing football with his friends.
   → Is he playing football with his friends?
5. We are studying English at the moment.
   → Are we studying English at the moment?
6. The baby is sleeping in the room.
   → Is the baby sleeping in the room?
7. Tom is listening to music.
   → Is Tom listening to music?
8. My parents are talking on the phone.
   → Are your parents talking on the phone? (Nếu bạn hỏi ai khác)
   Hoặc: Are my parents talking on the phone? (Nếu bạn tự hỏi)
9. You are wearing a red dress.
   → Are you wearing a red dress?
10. Anna and Lucy are doing their homework.
    → Are Anna and Lucy doing their homework

là sao bn