=\(\frac{-16}{5}.\frac{-15}{64}+\left(\frac{4}{5}-\frac{34}{15}\right):\frac{7}{2}\)

= \(\frac{-16.\left(-15\right)}{5.64}+\left(\frac{12}{15}-\frac{34}{15}\right).\frac{2}{7}\)

=\(\frac{-1.\left(-3\right)}{1.4}+\left(\frac{-22}{15}\right).\frac{2}{7}\)

=\(\frac{3}{4}-\frac{44}{105}=\frac{315}{420}-\frac{176}{420}=\frac{139}{420}\)

k mình nha

\(\left(-3,2\right).\frac{-15}{64}+\left(0,8-2\frac{4}{15}\right):3\frac{1}{2}\)

\(=0,75+\left(0,8-\frac{34}{15}\right):\frac{7}{2}\)

\(=0,75+\frac{46}{15}:\frac{7}{2}\)

\(=0,75+\frac{46}{15}.\frac{2}{7}\)

\(=0,75+\frac{92}{105}=\frac{683}{420}\)

A/   \(\left(15-6\frac{13}{18}\right):11\frac{1}{27}-2\frac{1}{8}:1\frac{11}{40}\)

\(=\left(15-\frac{121}{18}\right):\frac{298}{27}-\frac{17}{8}:\frac{51}{40}\)

\(=\left(\frac{270}{18}-\frac{121}{18}\right):\frac{298}{27}-\frac{17}{8}:\frac{51}{40}\)

\(=\frac{149}{18}:\frac{298}{27}-\frac{17}{8}:\frac{51}{40}\)

\(=\frac{3}{4}-\frac{5}{3}\)

\(=\frac{9}{12}-\frac{20}{12}\)\(=-\frac{11}{12}\)

B/  \(\left(-3,2\right)\cdot-\frac{15}{64}+\left(0,8-2\frac{4}{15}\right):3\frac{2}{3}\)

\(=\left(-3,2\right)\cdot-\frac{15}{64}+\left(0,8-\frac{34}{15}\right):\frac{11}{3}\)

\(=-\frac{3,2}{1}\cdot-\frac{15}{64}+\left(0,8-\frac{34}{15}\right):\frac{11}{3}\)

\(=\frac{48}{64}+\left(0,8-\frac{34}{15}\right):\frac{11}{3}\)

\(=\frac{3}{4}+\left(\frac{12}{15}-\frac{34}{15}\right):\frac{11}{3}\)

\(=\frac{3}{4}+\left(-\frac{22}{15}\right):\frac{11}{3}\)

\(=\frac{3}{4}+\left(-\frac{2}{5}\right)\)

\(=\frac{15}{20}+\left(-\frac{8}{20}\right)\)

\(=\frac{7}{20}\)

= 0

đúng

Vì k thứ hai bằng 0 cho nên tổng bằng 0

mình giúp cho

= -16 / 5 . -15 / 64 + ( 4 / 5 - 34 / 15 ) : 11 / 3

= - 16 / 5 . -15 / 64 + -22 / 15 : 11 / 3

= 3 / 4 + -22 / 15 : 11 / 3

= 3 / 4 + - 2 / 5

= 7 / 20

xong , lần sau nhớ giúp mình nhé ! bye

\(\frac{7}{20}\)đó bn, tính số thập phân ra phân số rồi tính lần lượt.thế nha  ^-^

\(=\frac{7}{20}\)

nha bạn

(-3,2) . \(\frac{-15}{64}\)+(0,8-2\(\frac{4}{15}\)):3\(\frac{2}{3}\)

=\(\frac{3}{4}\)+(-\(\frac{22}{15}\)):\(\frac{11}{3}\)

=\(\frac{3}{4}\)+\(\left(-\frac{22}{15}\right).\frac{3}{11}\)

=\(\frac{3}{4}\)-\(\frac{2}{5}=\frac{7}{20}\)

                    chọn đúng giúp mình nha!

sao bạn có thể viết được hỗn số và phân số?

dễ mà bạn chỉ cần bật ô trả lời chon biểu tượng giống chữ M nằm ngang nhé 

\(\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right)....\left(1-\frac{1}{2009}\right)\)

=\(\frac{1}{2}.\frac{2}{3}.\frac{3}{4}...\frac{2008}{2009}\)

=\(\frac{1}{2009}\)

\(1\frac{13}{15}\cdot3\cdot(0,5)^2\cdot3+\left[\frac{8}{15}-1\frac{19}{60}:1\frac{23}{24}\right]\)

\(=\frac{28}{15}\cdot3\cdot0,5\cdot0,5\cdot3+\left[\frac{8}{15}-\frac{79}{60}:\frac{47}{24}\right]\)

\(=\frac{28}{5}\cdot0,25\cdot3+\left[\frac{32}{60}-\frac{79}{60}\cdot\frac{24}{47}\right]\)

\(=\frac{28}{5}\cdot\frac{25}{100}\cdot3+\left[\frac{32}{60}-\frac{158}{235}\right]\)

\(=\frac{28}{5}\cdot\frac{1}{4}\cdot3+\frac{-98}{705}=\frac{7}{5}\cdot1\cdot3+\frac{-98}{705}\)

Đến đây là tính dễ rồi :v

\((-3,2)\cdot\frac{-15}{64}+\left[0,8-2\frac{4}{15}\right]:1\frac{23}{24}\)

\(=\frac{-32}{10}\cdot\frac{-15}{64}+\left[\frac{8}{10}-\frac{34}{15}\right]:\frac{47}{24}\)

\(=\frac{-32\cdot(-15)}{10\cdot64}+\left[\frac{4}{5}-\frac{34}{15}\right]:\frac{47}{24}\)

\(=\frac{-1\cdot(-3)}{2\cdot2}+\frac{4\cdot3-34}{15}:\frac{47}{24}\)

\(=\frac{3}{4}+\frac{-22}{15}:\frac{47}{24}\)

\(=\frac{3}{4}+\frac{-517}{180}=\frac{-191}{90}\)

Bài 2 : \(\frac{2\cdot(-13)\cdot9\cdot10}{(-3)\cdot4\cdot(-5)\cdot26}=\frac{1\cdot(-1)\cdot3\cdot2}{(-1)\cdot2\cdot(-1)\cdot2}=\frac{1\cdot3}{-1\cdot2}=\frac{3}{-2}=\frac{-3}{2}\)

\(\frac{15\cdot8+15\cdot4}{12\cdot3}=\frac{15\cdot(8+4)}{12\cdot3}=\frac{15\cdot12}{12\cdot3}=\frac{15}{3}=5\)

  (1-1/2)(1-1/3)(1-1/4)...(1-1/2009)

=1/2*2/3*3/4*...*2008/2009

=\(\frac{1\cdot2\cdot3\cdot...\cdot2008}{2\cdot3\cdot4\cdot...\cdot2009}\)

=1/2009

=1/2x2/3x3/4x...../2008/2009

=1/2009

=> 1/2.2/3.3/4...x/(x+1)=1/2009

=>  1/(x+1)=1/2009

=>   x+1=2009

=>   x=2008

Mik nhanh nhất mik nha

=> 1/2 . 2/3 . 3/4 .... x/x+1 = 1/2009

<=> (1.2.3...x) / [2.3...x.(x+1)] = 1/2009

<=> 1/ (x+1) = 1/2009

=> x+1=2009 => x=2008

tính gì