Nhỏ quá

ĐKXĐ: \(-1\le x\le3\)

Đặt \(\sqrt{x+1}+\sqrt{3-x}=t\ge\sqrt{x+1+3-x}=2\)

\(\Rightarrow4+2\sqrt{-x^2+2x+3}=t^2\)

\(\Rightarrow\sqrt{-x^2+2x+3}=\dfrac{t^2-4}{2}\) (1)

Phương trình trở thành:

\(t-\dfrac{t^2-4}{2}=2\)

\(\Leftrightarrow2t-t^2=0\Rightarrow\left[{}\begin{matrix}t=0\left(loại\right)\\t=2\end{matrix}\right.\)

Thế vào (1):

\(\Rightarrow\sqrt{-x^2+2x+3}=0\)

\(\Rightarrow\left[{}\begin{matrix}x=-1\\x=3\end{matrix}\right.\)

1.It takes me half an hour to get to work

2.Is this the cheapest computer you have?

3.How much does this dictionary cost?

5.Tom's collection has over eight hundred stamps

8.Như câu 1

9.Như câu 5

10.What terrible weather!

1.It takes me half an hour to get work

2.Is this the most expensive computer

3.How much does this dictionary cost?

4. You don't have to finish the work today

5.Tom's collection have over eight hundred stamps

6.We are interested in playing football match

7.You don't have as more books as me

8.It takes the boys three hours a day to learn the lessons

9.There are over 30 million books in the library contains

10.What terrible weather

Giải cụ thể từng bước cho dễ hiểu nhé các bạn

áp dụng ở khung nội dung mà làm, bạn hỏi mấy bài cơ bản vậy thì đi thi sao nắm được

toán lớp mấy đây " thánh"

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.

3:

a: \(P\left(x\right)=2x^4+2x^3-5x+3\)

\(Q\left(x\right)=4x^4-2x^3+2x^2+5x-2\)

b: P(-1)=2-2-3+5+3=5

Q(0)=4*0-2*0+2*0+5*0-2=-2

c: G(x)=2x^4+2x^3-5x+3+4x^4-2x^3+2x^2+5x-2

=6x^4+2x^2+1

d: G(x)=x^2(6x^2+2)+1>0 với mọi x

a: Xét (O) có 

ΔABC nội tiếp đường tròn
BC là đường kính

Do đó: ΔABC vuông tại A