Đặt tổng trên = A

\(A=\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}+\frac{3}{512}\)

\(A.4=6+\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}\)

\(A.4-A=\left(6+\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}\right)-\left(\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}+\frac{3}{512}\right)\)

\(A.3=6-\frac{3}{512}=\frac{3069}{512}\)

\(A=\frac{3069}{512}:3=\frac{1023}{512}\)

Đặt A = 3/2 + 3/8 + ... + 3/512
bn tách 
3/2 = 3/2^1
3/8 = 3/2^3
...
3/512 = 3/2^9
Rồi nhân nó lên trừ được bao nhiêu - đi A ban đầu là đc
k nka

lấy 6 đâu ra bạn 

512.(2 - 128) - 128.(-512) = 512.(2 - 128) - (-128).512 = 512.[2 - 128 - (-128)] = 512.2 = 1024

512 x ( 2 - 128 ) - 128 x ( - 512 )

= 512 x 2 - 512 x 128 - ( - 128) x 512

= 512 x (2 - 128 + 128 )

= 512 x 2

= 1024 

=512.2-512.128+128.512

=512.(2-128+128)

=512.2

=1024

a, S = 1/2 + 1/4 + 1/8 +........+ 1/512 

= \(\frac{1}{1.2}+\frac{1}{2.2}+\frac{1}{2.4}+...+\frac{1}{4.128}\)

\(\Rightarrow S=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+...+\frac{1}{4}-\frac{1}{128}\)

\(S=1-\frac{1}{128}=\frac{127}{128}\)

S = 1/2 + 1/4 + 1/8 + ... + 1/512

2S = 2 x ( 1/2 + 1/4 + 1/8 + ... + 1/512 )

2S = 1 + 1/2 + 1/4 + ... + 1/256

2S - S = ( 1 + 1/2 + 1/4 + ... + 1/256 ) - ( 1/2 + 1/4 + 1/8 + ... + 1/512 )

S = 1 - 1/512

S = 511/512

\(S=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{8}+...+\frac{1}{256}-\frac{1}{512}\)

\(=1-\frac{1}{512}\)

\(=\frac{511}{512}\)

= (512.2-512.128)-128.(-512)

=512.2-512.128-128.(-512)

=[512.128+128x (-512)]+512.2

=0+1024 

=1024

a, 23 + 52 = 75

b, (-13) - 317 = -330

c, |-23| + 15 = 23 + 15 = 38

d, (-512) - 7 = -519

23 + 52 = 75

(-13) + (-317) = -330

|-23| + 15 = 23 + 15 = 38

(-512) + (-7) = -519 

a) 75

b) -330

c) 38

d) -519

− 5 12 + 6 11 + 7 17 + 5 11 + 5 12 = − 5 12 + 5 12 + 6 11 + 5 11 + 7 17 = 0 + 1 + 7 17 = 24 17