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54 = 2.3³ 

42 = 2.3.7

48 = 2⁴.3

ƯCLN (54; 42; 48) = 2.3 = 6

ƯC (54; 42; 48) = Ư(6) = {1; 6; 2; 3}

Ta có:   \(54=2.3^3\)

            \(42=2.3.7\)

            \(48=2^4.3\)

\(\Rightarrow UCLN\left(54,42,48\right)=2.3=6\)

\(\Rightarrow UC\left(54,42,48\right)=U\left(6\right)=(\pm1,\pm2,\pm3,\pm6)\)

Vậy UC(54, 42, 48)= \(\left(\pm1,\pm2,\pm3,\pm6\right)\)

\(400\div\left\{5\left[360-\left(290+2.5^2\right)\right]\right\}\)

\(=400\div\left\{5\left[360-\left(290+50\right)\right]\right\}=400\div\left[5\left(360-340\right)\right]\)

\(=400\div\left(5.20\right)=400\div100=4\)

                                       Bài giải

\(400\text{ : }\left[5\left\{360-\left(290+2\cdot5^2\right)\right\}\right]\)

\(=400\text{ : }\left[5\left\{360-\left(290+50\right)\right\}\right]\)

\(=400\text{ : }\left[5\left\{360-340\right\}\right]\)

\(=400\text{ : }\left[5\cdot20\right]\)

\(=400\text{ : }100\)

\(=4\)

1) x² - 6x + 9 = (x² - 3x) -(3x - 9) = x(x - 3) - 3(x - 3) = (x - 3)(x - 3)

2) 25 + 10x + x² = x² + 5x + 5x + 25 = x(x + 5) + 5(x + 5) = (x + 5)(x + 5)

5) x² - 10x + 25 = x² - 5x - 5x + 25 = x(x - 5) - 5(x - 5) = (x - 5)(x - 5)

6) x² + 4xy + 4y² = x² + 2xy + 2xy + 4y² = x(x + 2y) + 2y(x + 2y) = (x + 2y)(x + 2y)

7) (3x + 2)² - 4 = (3x + 2)² - 2² = (3x + 2 - 2)(3x + 2 + 2) = 3x(3x +  4)

8) 4x² - 49 = (2x)² - 7² = (2x - 7)(2x + 7)

9) \(\frac{9}{25}x^4-\frac{1}{4}=\left(\frac{2}{3}\right)^2.\left(x^2\right)^2-\left(\frac{1}{2}\right)^2=\left(\frac{2}{3}x^2\right)^2-\left(\frac{1}{2}\right)^2=\left(\frac{2}{3}x^2-\frac{1}{2}\right)\left(\frac{2}{3}x^2+\frac{1}{2}\right)\)

10) x³² - 1 = (x¹⁶)² - 1² = (x¹⁶ - 1)(x¹⁶ + 1)

11 4x² + 4x + 1 = 4x² + 2x + 2x + 1 = 2x(2x + 1) + (2x + 1) = (2x + 1)(2x + 1)

12 x² - 20x - 100 = x² - 10x - 10x + 100 = x(x - 10) - 10(x - 10) = (x - 10)(x - 10)

13 y⁴ - 14y² + 49 = y⁴ - 7y² - 7y² + 49 = y²(y² - 7) - 7(y² - 7) = (y² - 7)²

Mk chỉ làm được đến đó thôi

 Định làm hết nhưng bạn kia làm đúng rồi ! Còn 2 câu làm nốt !!!!

                                   Bài giải

\(3,\text{ }\frac{1}{4}a^2+2ab+4b^2=\left(\frac{1}{2}a\right)^2+2ab+\left(2b\right)^2=\left(\frac{1}{2}a+2b\right)^2\)

\(4,\text{ }\frac{1}{9}-\frac{2}{3}y^4+y^8=\left(\frac{1}{3}\right)^2-2\cdot\frac{1}{3}y^4+\left(y^4\right)^2=\left(y^4+\frac{1}{3}\right)^2\)

\(A=\left(x-2\right)^2+\left(x+3\right)^2-2\left(x+1\right)\left(x-1\right).\)

\(A=x^2-4x+4+x^2+6x+9-2\left(x^2-1\right)\)

\(A=x^2-4x+4+x^2+6x+9-2x^2+2\)

\(A=2x+15\)

\(B=\left(x^2-y^2\right)\left(x^2+y^2\right)\left(x^4+y^4\right)\left(x^8+y^8\right)\)

\(B=\left(x^4-y^4\right)\left(x^4+y^4\right)\left(x^8+y^8\right)\)

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

\(B=x^{16}-y^{16}\)

VẬY \(B=x^{16}-y^{16}\)

đề bài là gì vậy ạ , bạn nên ghi rõ đề bài tránh hiểu nhầm

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

\(=2x^3-3x^2+5x-6x^2+9x-15\)

\(=2x^3-9x^2+14x-15\)

Ta có : \(A=\frac{1993.1995+28}{1993.\left(1995+1\right)-1965}=\frac{1993.1995+28}{1993.1995+1993-1965}=\frac{1993.1995+28}{1993.1995+28}=1\)

                                                           Bài giải

\(A=\frac{1993\cdot1995+28}{1993\cdot1996-1965}=\frac{1993\cdot1995+28}{1993\cdot1995+1993-1965}=\frac{1993\cdot1995+28}{1993\cdot1995+28}=1\)

Vậy A = 1

Có 2 cách viết tập hợp:

- Liệt kê các phần tử của tập hợp

- Chỉ ra tính chất đặc trưng của tập hợp

<=> /x/ = 67,38 - 21,38

<=> /x/ = 46

<=> \(\orbr{\begin{cases}x=46\\x=-46\end{cases}}\)

KÍ HIỆU: /x/ là giá trị tuyệt đối của x nhé.

67,38-|x|=21,38

<=>|x|=67,38-21,38

<=>|x|=46

<=>x=+-46

KQ đúng nha bn

Danang is known as the most worth – living city in Vietnam. Recently, it has become a new city which is very famous for tourism. Danang has many destinations which attract foreign tourists from all over the world. They can enjoy from Ba Na Hill on the top of the mountains to the unique Dragon Bridge in the center of the city, which can spit water and breath fire on the weekend. As a coastal city, Danang has many beautiful beaches such as My Khe beach with clear water and long white sand. Ngu Hanh Son mountain is also one of tourist attractions with many caves and impressive structures. Buddhists can visit Linh Ung pagoda and Tam Thai pagoda on that mountain. When going to Danang, tourists can go to other famous destinations nearby such as Hue – the ancient capital or Old Street Hoi An. Not only being famous for landscapes, Danang attracts tourists because of its cuisine. Vietnamese turmeric noodles, noodles with grilled pork, lemongrass pork skewers or crispy pancake are all traditional cuisine. Visitors can choose to relax in five stars hotel or luxury resorts too. In addition, local people are very polite, generous and kind. They are willing to show you the way if you are lost, show you delicious restaurants or even prestigious hotels. All the things above are the reasons why Danang has been visited and loved by visitors.

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