Lời giải:
BĐT cần chứng minh tương đương với:

$18a^2+3b^2+7c^2+18-16ac+6bc-12a\geq 0$

$\Leftrightarrow (16a^2-16ac+4c^2)+3(b^2+2bc+c^2)+2(a^2-6a+9)\geq 0$

$\Leftrightarrow (4a-2c)^2+3(b+c)^2+2(a-3)^2\geq 0$

(luôn đúng với mọi $a,b,c$ thực)

Do đó ta có đpcm.

\(\Leftrightarrow\left(x-y\right)\left(x+y\right)=2017=1.2017\)

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x-y=1\\x+y=2017\end{matrix}\right.\\\left\{{}\begin{matrix}x-y=-1\\x+y=-2017\end{matrix}\right.\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=1009\\y=1008\end{matrix}\right.\\\left\{{}\begin{matrix}x=-1009\\y=-1008\end{matrix}\right.\end{matrix}\right.\)

\(1,Fe+CuCl_2\rightarrow FeCl_2+Cu\)

\(2,\) không phản ứng

\(3,Na_2CO_3+2HNO_3\rightarrow2NaNO_3+CO_2+H_2O\\ 4,Không.phản.ứng\\ 5,Na_2SO_4+Ba\left(NO_3\right)_2\rightarrow BaSO_4+2NaNO_3\)

6, không phản ứng

7, không phản ứng

\(8,Mg\left(HCO_3\right)_2+Ba\left(OH\right)_2\rightarrow MgCO_3+BaCO_3+2H_2O\)

9, không phản ứng

\(10,2NaOH+FeCl_2\rightarrow Fe\left(OH\right)_2+2NaCl\)

11, Không phản ứng

Fe + CuCl₂ → FeCl₂ + Cu

Cu + FeCl₂ → Fe + CuCl₂

Na₂CO3 + HNO₃ → NaNO₃ + CO₂ ↑ + H₂O

  Na2SO4 +  HNO3   → NaNO₂ + H₂SO₄5, Na₂SO₄ +

Ba(NO₃ )₂ → NaNO₃ + BaSO₄

NaCl + Ba(NO3 )2 →NaNO3 + BaCl2 

NaNO3 + BaCl2 KHÔNG TÁC DỤNG ĐƯỢC 

Mg(HCO3)2 + Ba(OH)2 = MgCO3 + BaCO3 + H2O

2NaOH + BaCl2 → Ba(OH)2 + 2NaCl

 FeCl2 + NaOH → Fe(OH)2 + NaCl

NaOH + MgCO3 = Na2CO3 + Mg(OH)2

Mấy phép cuối tớ lười nên viết vậy cho nhanh nha<3

áp dụng định lý talet

Mid-Autumn Festival is a famous festival of Vietnam. On this occasion, children are the main characters to sing, carry lanterns, watch lion dances and sit together to eat sweets and drink soft drinks. The Mid-Autumn Festival is also considered a non-horror version of Halloween, where children will have fun holding lanterns with fairy-tale characters and different cartoon characters. Sweets do not need to beg and say "Give candy or be teased", at the middle school festival, most children are prepared with candy to have fun and eat as much as they want. This is one of the oldest festivals from ancient times to now, I'm sure other people from abroad will also enjoy this festival.

Đây là lần đầu mình viết văn bằng tiếng Anh nên có gì bạn thông cảm nha. 

The Mid-Autumn Festival, also known as Tet Trung Thu, is a joyous celebration in Vietnam. Held on the 15th day of the eighth lunar month, usually in September, this vibrant festival revolves around family reunions and the admiration of the full moon. Streets come alive with colorful lanterns, and children carry handmade lanterns while parading through neighborhoods. Mooncakes, a traditional delicacy, are shared among family and friends. The festival holds deep cultural significance, emphasizing gratitude and unity. Traditional lion dances, folk performances, and the enchanting glow of lantern-lit nights create a magical atmosphere during this beloved Vietnamese celebration.

\(2x^2y+4xy^2+2y^3-8\) 

\(=2y\left(x^2+2xy+y^2\right)-8\)

\(=2y\left(x+y\right)^2-8\) 

\(=2\left[y\left(x+y\right)^2-4\right]\)

thank you huỳnh thanh phong

Hoàn thành bộ với một từ hoặc phara từ hộp???
 

Chưa có đề bài ạ

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

\(=\left(x^2+2\cdot5\cdot x+5^2\right)-\left(x^2+3x-2x-6\right)\)

\(=\left(x^2+10x+25\right)-\left(x^2+x-6\right)\)

\(=x^2+10x+25-x^2-x+6\)

\(=9x+31\)

\((x+5)^2-(x+3)(x-2)\\=(x^2+2\cdot x\cdot5+5^2)-[x(x-2)+3(x-2)]\\=(x^2+10x+25)-(x^2-2x+3x-6)\\=x^2+10x+25-(x^2+x-6)\\=x^2+10x+25-x^2-x+6\\=(x^2-x^2)+(10x-x)+(25+6)\\=9x+31\)