\(\left[a+\left(b+c\right)\right]^2\\=a^2+2a\left(b+c\right)+\left(b+c\right)^2\\ =a^2+2ab+2ac+\left(b^2+2bc+c^2\right)\\ =a^2+b^2+c^2+2ab+2ac+2bc\)

ê

M là trung điểm của đoạn nào vậy bạn?

/u:/: fruit, cruise, rude, flu, school, clue, through, shoe

/ʊ/: good, pull, full, could, wood, book, put

Cột 1:  fruit, cruise, rude, flu, school, clue, through, shoes

Cột 2: còn lại  

a: ΔABC cân tại A

mà AD là đường cao

nên D là trung điểm của BC

ΔADB vuông tại D

=>\(DA^2+DB^2=AB^2\)

=>\(DB=\sqrt{5^2-4^2}=3\left(cm\right)\)

b: Xét ΔHDB vuông tại D và ΔHEA vuông tại E có

\(\widehat{DHB}=\widehat{EHA}\)(hai góc đối đỉnh)

Do đó: ΔHDB~ΔHEA

=>\(\dfrac{HD}{HE}=\dfrac{HB}{HA}\)

=>\(HD\cdot HA=HB\cdot HE\)

Giúp mình làm vs

\(\dfrac{x^2+4+6}{5-6x}< 0\)

Nhận xét:

\(x^2\ge0,\forall x\)

\(\Rightarrow x^2+4+6\ge10,\forall x\)

Do đó \(\dfrac{x^2+4+6}{5-6x}< 0\) khi và chỉ khi:

\(5-6x< 0\)

\(\Leftrightarrow6x>5\)

\(\Leftrightarrow x>\dfrac{5}{6}\)

Vậy \(x>\dfrac{5}{6}\)

Sửa đề:

   Do (x + 2)² ≥ 0

(x + 2)² + 2 > 0

5 - 6x < 0

-6x < -5

\(\sqrt{x}=1-\sqrt{3}\)

Nhận xét:

\(\sqrt{3}>\sqrt{1}=1\)

\(\Rightarrow1-\sqrt{3}< 0\)

\(\Rightarrow\sqrt{x}< 0\) (vô lí)

Vậy không tìm được giá trị x thoả mãn đề bài

\(\left(a+1\right)\left(a+2\right)\left(a+3\right)\left(a+4\right)+1\\ =\left[\left(a+1\right)\left(a+4\right)\right]\left[\left(a+2\right)\left(a+3\right)\right]+1\\ =\left(a^2+5a+4\right)\left(a^2+5a+6\right)+1\\ =\left(a^2+5a+4\right)\left(a^2+5a+4\right)+2\left(a^2+5a+4\right)+1\\ \left(a^2+5a+4\right)^2+2\left(a^2+5a+4\right)+1\\ =\left(a^2+5a+5\right)^2\)

It was a long time before we came _____to_____ the truth. 

(come to: đạt được, phát hiện ra điều gì đó)

The dog came _____at_____ us with teeth bared.

(come at: tiếp cận với thái độ hung hăng hoặc thù địch)

Come _____on_____ ! We are late for the bus.

(come on: đây là lời thúc giục di chuyển: nhanh lên)

How is your English coming ____along______ ?

(come along: phát triển, tiến đến)

I was picking up the teapot when it came __apart________ in my hands.

(come apart: rơi ra, tách ra, rời rạc)

She has been very ill, but now she is coming ___round_______ fine.

(com round: hồi phục, khôi phục)

We must not let this silly quarrel come ___between_______ us.

(come between: gây cản trở, tạo ra rào cản)

I come _____from_____ Liverpool, but I have spent most of my life in Scotland.

(come from: đến từ)

John has come __into________ the money; he inherited £5,000.

(come into: thừa kế)

The town came _____into_____ sight when we turned the bend.

(come into: xuất hiện)

The hook came ____off______ the wall when I hung up my coat

(come off: bong ra, rời ra)

This tool will come ____in______ very handy for my uncle.

(come in handy: có ích)

Snails come ____out______ as soon as it rains.

(come out: xuất hiện)

When did you first come ____over______ to Europe?

(come over: di chuyển)

Your talk came ______to____ very well.

(come to: kết quả là, dẫn đến)

It has come _____to_____ my attention that he is very short-tempered.

He came ______to____ the conclusion that someone was having an affair with his wife.

He came _______up___ and asked me if I had the time.

(come up: xảy ra, xuất hiện)

Much of the tea consumed in England comes __from________ Sri Lanka.

(come from: đến từ)

He comes ____from______ an interesting family.

How’s your orchard coming _____along_____ ?

Sometimes it’s very difficult to come ___to_______ the truth.

He never lets anything come ______between____ him and his morning paper.

It was a long time before we came ___to_______ the truth.
The dog came _____at_____ us with teeth bared.
Come ____on______ ! We are late for the bus.
How is your English coming ____along______ ?
I was picking up the teapot when it came ______âpart____ in my hands.
She has been very ill, but now she is coming ______round____ fine.
We must not let this silly quarrel come ____between______ us.
I come ______from____ Liverpool, but I have spent most of my life in Scotland.
John has come _____into_____ the money; he inherited £5,000.
The town came ______into____ sight when we turned the bend.