5/2 + 5/4 + 5/8 + 5/16 + 5/32 + 5/64 

= 5(1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64)

Đặt A = 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64

=> 2A = 1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32

=> 2A - A = 1 - 1/64

=> A = 1 - 1/64

Do đó : 5(1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64) = 5(1 - 1/64) = 5 . 63/64 = 315/64 

nhanh len gium minh duoc ko

\(2A=5+\frac{5}{2}+\frac{5}{4}+\frac{5}{8}+\frac{5}{16}+\frac{5}{32}.\)

\(A=2A-A=5-\frac{5}{64}=\frac{315}{64}\)

\(\frac{1}{2}.\left(\frac{1}{3}-\frac{1}{11}\right)\)

\(=\frac{1}{2}\times\frac{8}{33}\)

\(=\frac{4}{33}\)

*Cách làm làm trong ngoặc tròn trước rồi nhân :v

\(\frac{1}{2}\)x(\(\frac{1}{3}\)-\(\frac{1}{11}\))

=\(\frac{8}{66}\)

1/2.(1/3-1/11)

= 1/2.8/33

= 4/33

\(\frac{2}{7}-x=\frac{-3}{4}\)

            \(x=\frac{2}{7}-\frac{-3}{4}\)

            \(x=\frac{8}{28}+\frac{21}{28}=\frac{29}{28}\)

vậy \(x=\frac{29}{28}\)

chúc bn học tốt!

= 2/7-  -3/4

= 8/28 + 21/28

= 29/28

vậy x =29/28

~Study Well~

tk mk nha

2/7-x=-3/4

x=2/7-(-3/4)

x=2/7+3/4

x=8/28+21/28

X=29/28

Ko bit

\(\frac{x+24}{1996}+\frac{x+25}{1995}+\frac{x+26}{1994}+\frac{x+27}{1993}+\frac{x+2036}{4}=0\)

\(\Leftrightarrow\frac{x+24}{1996}+1+\frac{x+25}{1995}+1+\frac{x+26}{1994}+\frac{x+27}{1993}+1+\frac{x+2036}{4}-4==0\)

\(\Leftrightarrow\frac{x+2020}{1996}+\frac{x+2020}{1995}+\frac{x+2020}{1994}+\frac{x+2020}{1993}+\frac{x+2020}{4}=0\)

\(\Leftrightarrow\left(x+2020\right)\left(\frac{1}{1996}+\frac{1}{1995}+\frac{1}{1994}+\frac{1}{1993}+\frac{1}{4}\right)=0\)

<=> x+2020=0 \(\left(\frac{1}{1996}+\frac{1}{1955}+\frac{1}{1994}+\frac{1}{1993}+\frac{1}{4}\right)=0\)

<=> x=-2020

Mình sửa lại dòng thứ 2 từ dưới lên

\(\Leftrightarrow x+2020=0\left(\frac{1}{1996}+\frac{1}{1995}+\frac{1}{1994}+\frac{1}{1993}+\frac{1}{4}\ne0\right)\)

<=> x=-2020

Vậy x=-2020

Mình cần giúp. Ai đó có thể giúp mình đc ko zậy

=\(\frac{12}{16}+\frac{3}{16}+\frac{3}{16}\)

=\(\frac{18}{16}=\frac{9}{8}\)

\(c1:\frac{3}{4}+\frac{3}{16}+\frac{3}{16}=\frac{15}{16}+\frac{3}{16}=\frac{9}{8}.\)

\(c2:\frac{3}{4}+\frac{3}{16}+\frac{3}{16}=\frac{3}{4}+\frac{6}{16}=\frac{9}{8}\)

3/4 + ( 3/16+3/16) = 3/4 + 6/16 = 18/16

a, \(\left(\frac{1}{5}-\frac{1}{4}\right)^2=\left(\frac{-1}{20}\right)^2=\frac{1}{400}\)

b, \(\left(\frac{5}{3}+\frac{1}{2}\right):\frac{-13}{5}+1\frac{5}{6}\)

=> \(\frac{13}{6}:\frac{-13}{5}+\frac{11}{6}\)

=> \(\frac{13}{6}.\frac{5}{-13}+\frac{11}{6}\)

=> \(\frac{-5}{6}+\frac{11}{6}=\frac{6}{6}=1\)

c, \(\left(\frac{3}{17}\right)^4.\left(\frac{-17}{6}\right)^4\)

=> \(\left(\frac{3}{17}.\frac{-17}{6}\right)^4=\left(\frac{-1}{2}\right)^4=\frac{1}{16}\)

đúng 100%

a) \(\left(\frac{1}{5}-\frac{1}{4}\right)^2=\left(-\frac{1}{20}\right)^2=\frac{1}{400}.\)

b) \(\left(\frac{5}{3}+\frac{1}{2}\right):-\frac{13}{5}+1\frac{5}{6}\)

= \(\frac{13}{6}:\left(-\frac{13}{5}\right)+\frac{11}{6}\)

= \(\left(-\frac{5}{6}\right)+\frac{11}{6}\)

= \(1.\)

c) \(\left(\frac{3}{17}\right)^4.\left(-\frac{17}{6}\right)^4\)

= \(\left[\frac{3}{17}.\left(-\frac{17}{6}\right)\right]^4\)

= \(\left(-\frac{1}{2}\right)^4=\frac{1}{16}.\)

Chúc bạn học tốt!

Đặt A = \(\frac{1}{101}+\frac{1}{102}+\frac{1}{103}+...+\frac{1}{150}\)(50 số hạng)

=> A > \(\frac{1}{150}+\frac{1}{150}+\frac{1}{150}+...+\frac{1}{150}\)(50 số hạng)

=> A > \(\frac{1}{150}.50\)

=> A > \(\frac{1}{3}\)

=> \(\frac{1}{101}+\frac{1}{102}+\frac{1}{103}+...+\frac{1}{150}\) > \(\frac{1}{3}\)(Đpcm)

từ \(\frac{1}{101}\)đến \(\frac{1}{150}\)có 50 phân số.

có :\(\frac{1}{101}\)lớn hơn \(\frac{1}{150}\)

\(\frac{1}{102}\)lớn hơn \(\frac{1}{150}\)........cứ như vậy cho đến \(\frac{1}{149}\)lớn hơn \(\frac{1}{150}\).suy ra tổng 50 phân số đã cho lớn hơn 50 nhân vơi \(\frac{1}{150}\)=\(\frac{1}{3}\)