\(\sqrt{15-\sqrt{216}}+\sqrt{33-12\sqrt{6}}=\sqrt{6-6\sqrt{6}+9}+\sqrt{24-12\sqrt{6}+9}=\sqrt{\left(3-\sqrt{6}\right)^2}+\sqrt{\left(\sqrt{24}-3\right)^2}=\left|3-\sqrt{6}\right|+\left|\sqrt{24}-3\right|=3-\sqrt{6}+\sqrt{24}-3=2\sqrt{6}-\sqrt{6}=\sqrt{6}\)

\(\dfrac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}=-\dfrac{\sqrt{2}\left(\sqrt{6}-4\right)}{\sqrt{3}\left(\sqrt{6}-4\right)}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{6}\left(\sqrt{5}+\sqrt{27}\right)}=\dfrac{-\sqrt{2}}{\sqrt{3}}-\dfrac{1}{\sqrt{6}}=\dfrac{-\sqrt{6}}{3}-\dfrac{\sqrt{6}}{6}=-\dfrac{\sqrt{6}}{2}\).

\(\sqrt{\dfrac{2-\sqrt{3}}{2+\sqrt{3}}}+\sqrt{\dfrac{2+\sqrt{3}}{2-\sqrt{3}}}=\dfrac{\left(\sqrt{2-\sqrt{3}}\right)^2+\left(\sqrt{2+\sqrt{3}}\right)^2}{\sqrt{2+\sqrt{3}}.\sqrt{2-\sqrt{3}}}=\dfrac{4}{1}=4\)

Bài 1: Thực hiện các phép tính sau:

\(a)\)Chưa rỏ đề

\(b)\)\(5025\div5-25\div5\)

\(=\)\(1005-5\)

\(=\)\(1000\)

\(c)\)\(218-180\div2\div9\)

\(=\)\(218-10\)

\(=\)\(208\)

\(d)\)\(\left(328-8\right)\div32\)

\(=\)\(320\div32\)

\(=\)\(10\)

Bài 1:

a) ( Tôi không nhìn rõ đầu bài )

b) 5025  :  5  -  25  :  5

=  ( 5025  -  25 )  :  5

=        5000   :   5

=       1000

c)   218  -  180  :  2  :  9

=     218   -    180  :  (  2  .  9 )

=      218    -    180   :  18

=       218    -    10

=       208

d)   (  328  -  8  )  :  32

=      320   :   32

=     10 

Bài 2: Thực hiện phép tính:

\(a)\)\(27.75+25.27-150\)

\(=\)\(27.\left(75+25\right)-150\)

\(=\)\(27.100-150\)

\(=\)\(2700-150\)

\(=\)\(2550\)

\(b)\)\(12\div\left\{400\div\left[500-\left(125+25.7\right)\right]\right\}\)

\(=\)\(12\div\left\{400\div\left[500-\left(125+175\right)\right]\right\}\)

\(=\)\(12\div\left\{400\div\left[500-300\right]\right\}\)

\(=\)\(12\div\left\{400\div200\right\}\)

\(=\)\(12\div2\)

\(=\)\(6\)

\(c)\)\(13.17-256\div16+14\div7-1\)

\(=\)\(221-16+2-1\)

\(=\)\(206\)

\(d)\)\(18\div3+182+3.\left(51\div17\right)\)

\(=\)\(6+182+3.3\)

\(=\)\(6+182+9\)

\(=\)\(197\)

Mk thấy bài 1 và 2 dễ nên bạn tự làm nha

3

+)Ta có n-2 \(⋮\)n-2

=>2.(n-2)\(⋮\)n-2

=>2n-4\(⋮\)n-2(1)

+)Theo bài ta có:2n+1\(⋮\)n-2(2)

+)Từ (1) và (2)

=>(2n+1)-(2n-4)\(⋮\)n-2

=>2n+1-2n+4\(⋮\)n-2

=>5\(⋮\)n-2

=>n-2\(\in\)Ư(5)={\(\pm\)1;\(\pm\)5}

+)Ta có bảng:

Vậy n\(\in\){1;3;-3;7}

Chúc bn học tốt

a. 5.(–8).( –2).(–3)                                                       b. 4.(–5)2 + 2.(–5) – 20

=(-5).8.(-2).(-3)                                                               ={(-5).2} {4+1}-20

=(-5)(-2)(-3).8                                                                 =(-10).5-20=-50-20=-70

=10.(-24)=-240

Bài 2: 

a: =>x-35=-23

=>x=12

b: =>|x-8|=13

=>x-8=13 hoặc x-8=-13

=>x=21 hoặc x=-5

Bài 1: 

a: =42-98-42+12-12=-98

b: =10x4x3x(-25)=40x(-25)x3=-1000x3=-3000

a) A=625–(61–17).12+(27+27):17A=625–(61–17).12+(27+27):17

=625–528+3=100=625–528+3=100

b) B=−126–(42–5)2+870:29B=−126–(42–5)2+870:29

=−126–112+30=−126–112+30

=−126–121+30=−217

a: \(=625-44\cdot12+\dfrac{41}{17}=97+\dfrac{41}{17}=\dfrac{1690}{17}\)

b: \(=-126-11^2+30=-126-121+30=-217\)

câu 1) 

\(\dfrac{-12}{18}+\left(\dfrac{-21}{35}\right)=\dfrac{-19}{15}\)
câu 2) 

\(-\dfrac{3}{21}+\dfrac{6}{42}=0\)
câu 3)

\(-\dfrac{18}{24}+\dfrac{15}{21}=-\dfrac{1}{28}\)
câu 4) 

\(\dfrac{1}{6}+\dfrac{2}{5}=\dfrac{17}{30}\)
câu 5) 

\(\dfrac{3}{5}+\left(-\dfrac{7}{4}\right)=-\dfrac{23}{20}\)
câu 6) 

\(\left(-2\right)+\left(\dfrac{-5}{8}\right)=\dfrac{-21}{8}\)
câu 7) 

\(\dfrac{1}{-8}+\left(-\dfrac{5}{9}\right)=-\dfrac{49}{72}\)
câu 8) 

\(\dfrac{4}{13}+\dfrac{12}{39}=\dfrac{8}{13}\)
câu 9) 

\(\dfrac{1}{21}+\dfrac{1}{28}=\dfrac{1}{12}\)
câu 10) 

\(-\dfrac{3}{29}+\dfrac{16}{58}=\dfrac{5}{29}\)
câu 11) 

\(\dfrac{8}{40}+\left(-\dfrac{36}{45}\right)=-\dfrac{3}{5}\)
câu 12) 

\(-\dfrac{8}{18}+\left(-\dfrac{15}{27}\right)=-1\)
câu 13) 

\(\dfrac{13}{30}+\left(-\dfrac{1}{5}\right)=\dfrac{7}{30}\)
câu 14) 

\(\dfrac{2}{21}+\dfrac{1}{28}=\dfrac{11}{84}\)
câu 15) 

\(5+\left(-\dfrac{3}{4}\right)=\dfrac{17}{4}\)
câu 16) 

\(\dfrac{18}{24}+\dfrac{45}{-10}=-\dfrac{15}{4}\)

ngu

Giải:

a)(-7/15-27/70)-(8/15+43/70)

=-7/15-27/70-8/15-43/70

=(-7/15-8/15)+(-27/70-43/70)

=-1+(-1)

=-2

b)3/7+(-1/5+-3/7)

=3/7-1/5+-3/7

=(3/7+-3/7)-1/5

=0-1/5

=-1/5

c)(4-12/5).25/8-2/5:-4/25

=8/5.25/8-(-5/2)

=5+5/2

=15/2

d)(-5/24+3/4-7/12):(-5/16)

=-1/24:(-5/16)

=2/15

e)-5/7.2/11+-5/7.9/11

=-5/7.(2/11+9/11)

=-5/7.1

=-5/7

g)6/7+5/4:(-5)-(-1/28).(-2)²

=6/7+(-1/4)-(-1/28).4

=6/7+(-1/4)-(-1/7)

=6/7-1/4+1/7

=(6/7+1/7)-1/4

=1-1/4

=3/4

Chúc bạn học tốt!