a) \(\frac{-3}{16}+\frac{-7}{16}+\frac{6}{-16}\)

\(=-\frac{3}{16}+-\frac{7}{16}+\frac{-6}{16}\)

\(=\frac{\left(-3\right)+\left(-7\right)+\left(-6\right)}{16}\)

\(=\frac{-16}{16}=-1\)

b) \(\frac{2}{5}-\frac{1}{7}+\frac{7}{10}\)

\(=\frac{28}{70}-\frac{10}{70}+\frac{49}{70}\)

\(=\frac{28-10+49}{70}\)

\(=\frac{67}{70}\)

c) \(3+\frac{1}{3}-2\frac{1}{2}\)

\(=\frac{3}{1}+\frac{1}{3}-\frac{5}{2}\)

\(=\frac{18}{6}+\frac{2}{6}-\frac{15}{6}\)

\(=\frac{18+2-15}{6}\)

\(=\frac{5}{6}\)

d) \(-\frac{3}{5}-\left(-\frac{2}{15}\right)\)

\(=-\frac{3}{5}+\frac{2}{15}\)

\(=\frac{-9}{15}+\frac{2}{15}\)

\(=-\frac{7}{15}\)

\(\frac{-3}{16}\)+(\(\frac{-7}{16}\) ) +(\(\frac{6}{-16}\))

=\(\frac{-3-7-6}{16}\)

=\(\frac{-16}{16}\)= \(-1\)

\(\frac{2}{5}\)\(-\)\(\frac{1}{7}\)+\(\frac{7}{10}\)

=\(\frac{9}{35}\)+\(\frac{7}{10}\)

=\(\frac{67}{70}\)

3+ \(\frac{1}{3}\)\(-\) \(\frac{21}{2}\)

=\(\frac{18+2-63}{6}\)

=\(\frac{-43}{6}\)

\(\frac{-3}{5}\)\(-\)(\(\frac{-2}{15}\))

=\(\frac{-3}{5}\)+\(\frac{2}{15}\)

=\(\frac{-9+2}{15}\)

=\(\frac{-7}{15}\)

Bài 1: 

b) Ta có: \(D=\dfrac{-5}{10}\cdot\dfrac{-4}{10}\cdot\dfrac{-3}{10}\cdot...\cdot\dfrac{3}{10}\cdot\dfrac{4}{10}\cdot\dfrac{5}{10}\)

\(=\dfrac{-5}{10}\cdot\dfrac{-4}{10}\cdot\dfrac{-3}{10}\cdot...\cdot0\cdot...\cdot\dfrac{3}{10}\cdot\dfrac{4}{10}\cdot\dfrac{5}{10}\)

=0

0,2-0,375+5/11/-0,3+9/16-15/22

5.10⁴+4.10³.16².5.10+9

=5.10000+4.1000.6.256+5.5.10+9

=50000+4000.1536+5.50+9

=54000.1536+250+9

=82944000+250+9

=82944259

Ta đặt

\(A=\dfrac{16}{10}+\dfrac{16}{90}+...+\dfrac{16}{3034}+\dfrac{16}{3690}\)

\(A=\dfrac{8}{5}+\dfrac{8}{45}+...+\dfrac{8}{1517}+\dfrac{8}{1845}\)

\(A=\dfrac{8}{1\times5}+\dfrac{8}{5\times9}+...+\dfrac{8}{37\times41}+\dfrac{8}{41\times45}\)

\(\dfrac{4}{8}\times A=\dfrac{4}{1\times5}+\dfrac{4}{5\times9}+...+\dfrac{4}{37\times41}+\dfrac{4}{41\times45}\)

\(\dfrac{1}{2}\times A=1-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{9}+...+\dfrac{1}{37}-\dfrac{1}{41}+\dfrac{1}{41}-\dfrac{1}{45}\)

\(\dfrac{1}{2}\times A=1-\dfrac{1}{45}\)

\(\dfrac{1}{2}\times A=\dfrac{44}{45}\)

\(A=\dfrac{44}{45}\times2\)

\(A=\dfrac{88}{45}\)

Nhân hết ra là xong, ez ghê

\(\left(3x-1\right)\left(2x+7\right)-\left(x+1\right)\left(6x-5\right)=10\)

\(\Leftrightarrow6x^2+21x-2x-7-6x^2+5x-6x+5=10\)

\(\Leftrightarrow18x-2=10\Leftrightarrow x=\frac{2}{3}\)

a. = (-17+17)+5+8

= 0+13 = 13

b. = (30-20)+(-12+12)

= 10+0 = 10

c. = (-4)+(-6)+(-440+440)

= -10 + 0 = -10

d. = (-5)+(-10)+(16-1)

= -15+15 = 0

Bạn ơi hình như câu b bạn lạc đề rồi 

a; \(\dfrac{3}{11}\) + \(\dfrac{5}{-9}\) + \(\dfrac{4}{11}\) - \(\dfrac{4}{9}\) + \(\dfrac{3}{17}\) + \(\dfrac{15}{11}\)

= (\(\dfrac{3}{11}\) + \(\dfrac{4}{11}\) + \(\dfrac{15}{11}\)) - (\(\dfrac{5}{9}\) + \(\dfrac{4}{9}\)) + \(\dfrac{3}{17}\)

= 2 - 1 + \(\dfrac{3}{17}\)

= 1 + \(\dfrac{3}{17}\)

= \(\dfrac{20}{17}\) 

c; N = \(\dfrac{\dfrac{5}{7}-\dfrac{5}{9}-\dfrac{5}{11}}{\dfrac{15}{7}+\dfrac{15}{9}+\dfrac{15}{11}}\)

   Phải là - \(\dfrac{5}{7}\) chỗ tử số mới đúng em nhé!

d; \(\dfrac{4+\dfrac{4}{73}\times\dfrac{1}{23}}{5+\dfrac{5}{73}\times\dfrac{1}{23}}\)

= \(\dfrac{4\times\left(1+\dfrac{1}{73\times23}\right)}{5\times\left(1+\dfrac{1}{73\times23}\right)}\)

=  \(\dfrac{4}{5}\)

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20

=(1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)+20+10

=20+20+20+20+20+20+20+20+20+20+10

=20×10+10

=200+10

=210

= ( 1 + 19 ) + ( 2 + 18 ) + ( 3 + 17 ) + (4 + 16 ) + ( 5 + 15 ) + ( 6 + 14 ) + ( 7 + 13 ) + ( 8 + 12) + ( 9+ 11 ) + 20

= 20 + 20 + 20 +20 +  20 +20 + 20 + 20 + 20 +20

= 20 x 10

= 200

tui đầu tiên đó 

Ta có : \(1+2+3+...+19+20\)

          \(=\frac{\left(20+1\right).20}{2}=\frac{21.20}{2}=210\)

1/ 2 + 2 = 4

2/ 4 + 4 = 8

3/ 8 + 8 = 16

4/ 16 + 16 = 32

5/ 32 + 32 =64

6/ 64 + 64 =128

7/ 128 + 128 =256

8/  256 + 256 =512

9/ 521 + 512 =1033

10/ 2048 + 2048 =4096

k mình đi

4

8

16

32

64

128

256

512

2048

4096