Tìm x:

a) 5\(\frac{4}{7}\): x =13

b) \(\frac{4}{7}\)x=\(\frac{9}{8}\)-0,125

c) \(\frac{2}{3}\)x-\(\frac{1}{2}\)=\(\frac{1}{10}\)

d) \(\frac{1}{3}\)x-0,5x = -1\(\frac{1}{4}\)

e) \(\frac{-5}{6}\)- x = \(\frac{7}{12}\)+ \(\frac{-1}{3}\)

f) \(\frac{x+2}{3}\)=\(\frac{x-2}{2}\)

g) \(\frac{2}{5}\)- \(\frac{1}{5}\): x = -25%

h) (2\(\frac{4}{5}\)x - 50): \(\frac{2}{3}\)= 51

i) \(\frac{2}{3}\)x -\(\frac{1}{2}\)x =\(\frac{5}{12}\)

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

k) (x : 6\(\frac{2}{7}\)+\(\frac{3}{7}\)) :2\(\frac{1}{5}\)-\(\frac{3}{7}\)= -2

l) (x +\(\frac{1}{5}\))² +\(\frac{17}{25}\)=\(\frac{26}{25}\)

m) (x +\(\frac{1}{2}\))(\(\frac{2}{3}\)- 2x) =0

Mọi người ơi giúp mình nhanh nha.

Ai giúp mình thì mình sẽ tick cho.

Tìm x\(\in\)Z biết :

a \(\frac{2}{2\times3}\)+ \(\frac{2}{3\times4}\)+ \(\frac{2}{4\times5}\)+  ... + \(\frac{2}{X\left(X+1\right)}\) = \(\frac{2007}{2009}\)

b \(\frac{1}{10}\)+ \(\frac{1}{40}\) + \(\frac{1}{88}\) + ... +  \(\frac{1}{\left(3x+2\right)\left(3x+5\right)}\) = \(\frac{4}{25}\)

                                                                                  Giải

a \(\frac{2}{2\times3}\)+ \(\frac{2}{3\times4}\) + ... + \(\frac{2}{x\left(x-1\right)}\)= \(\frac{2007}{2009}\)

\(\Leftrightarrow\)2(\(\frac{1}{2}\) \(-\) \(\frac{1}{3}\) + \(\frac{1}{3}\) \(-\)\(\frac{1}{4}\) + ... + \(\frac{1}{x}\) \(-\) \(\frac{1}{x+1}\))  = \(\frac{2007}{2009}\) \(\Leftrightarrow\)\(\frac{1}{2}\) \(-\)\(\frac{1}{x+1}\)= \(\frac{2007}{4018}\)

\(\Leftrightarrow\)\(\frac{1}{x+1}\)= \(\frac{1}{2}\)\(-\)\(\frac{2007}{4018}\) \(\Leftrightarrow\) \(\frac{1}{x+1}\) =\(\frac{1}{2009}\)\(\Leftrightarrow\)x + 1 = 2009 \(\Leftrightarrow\)x = 2008

b \(\frac{1}{10}\) + \(\frac{1}{40}\) + \(\frac{1}{88}\) + ... + \(\frac{1}{\left(3x+2\right)\left(3x+5\right)}\)= \(\frac{4}{25}\)

\(\Leftrightarrow\) \(\frac{1}{2\times5}\) + \(\frac{1}{5\times8}\) + \(\frac{1}{8\times11}\) + ... + \(\frac{1}{\left(3x+2\right)\left(3x+5\right)}\) = \(\frac{4}{25}\)

\(\Leftrightarrow\) \(\frac{1}{3}\)(\(\frac{3}{2\times5}\) + \(\frac{3}{5\times8}\) + \(\frac{3}{8\times11}\) + ... + \(\frac{3}{\left(3x+2\right)\left(3x+5\right)}\) ) = \(\frac{4}{25}\)

\(\Leftrightarrow\) \(\frac{1}{3}\)(\(\frac{1}{2}\)\(-\)\(\frac{1}{5}\) + \(\frac{1}{5}\) \(-\)\(\frac{1}{8}\)+ ...+  \(\frac{1}{3x+2}\) \(-\)\(\frac{1}{3x+5}\)) =  \(\frac{4}{25}\)\(\Leftrightarrow\)\(\frac{1}{2}\)\(-\)\(\frac{1}{3x+5}\)=\(\frac{12}{25}\)

\(\Leftrightarrow\)\(\frac{1}{3x+5}\) =\(\frac{1}{2}\)\(-\)\(\frac{12}{25}\) \(\Leftrightarrow\) 3x + 5 = 50 \(\Leftrightarrow\)3x = 45 \(\Leftrightarrow\) x = 15                                                                    Các bạn có cách làm giống mình thì trả lời nhé               

Tìm x biết :

a) \(\frac{2}{3}\)x - \(\frac{1}{2}\)= \(\frac{1}{10}\)

b) ( \(2\frac{4}{5}\)x - 50 ) :\(\frac{2}{3}\)= 51

c) \(\frac{2}{3}\)x - \(\frac{1}{2}\)x = \(\frac{5}{12}\)

d) \(\frac{17}{2}\)- | 2x - \(\frac{3}{4}\)| = \(-\frac{7}{4}\)

đ) ( x + \(\frac{1}{5}\))² + \(\frac{17}{25}\)= \(\frac{26}{25}\)

Tìm x biết :

a) \(\frac{2}{3}\)x - \(\frac{1}{2}\)= \(\frac{1}{10}\)

b) ( \(2\frac{4}{5}\)x - 50 ) : \(\frac{2}{3}\)= 51

C) \(\frac{2}{3}\)x - \(\frac{1}{2}\)x = \(\frac{5}{12}\)

D) \(\frac{17}{2}\)- | 2x - \(\frac{3}{4}\)| = \(-\frac{7}{4}\)

Đ) ( x + \(\frac{1}{5}\))² + \(\frac{17}{25}\)= \(\frac{26}{25}\)

Thực hiện phép tính:

a) (\(\frac{3}{8}\)+ \(\frac{-3}{4}\)+ \(\frac{7}{12}\)) : \(\frac{5}{6}\)+ \(\frac{1}{2}\)

b) \(\frac{1}{2}\)+ \(\frac{3}{4}\)- (\(\frac{3}{4}\)- \(\frac{4}{5}\))

c) \(6\frac{5}{12}\): \(2\frac{3}{4}\)+ \(11\frac{1}{4}\). (\(\frac{1}{3}\)- \(\frac{1}{5}\))

d) (\(\frac{7}{8}\)- \(\frac{3}{4}\)) . \(1\frac{1}{3}\)- \(\frac{2}{7}\). (3,5)²

e) (\(\frac{3}{5}\)+ 0,415 - \(\frac{3}{200}\)) .\(2\frac{2}{3}\). 0,25

f) \(\frac{5}{16}\): 0,125 - (\(2\frac{1}{4}\)- 0,6) . \(\frac{10}{11}\)

g) 0,25 : (10,3 - 9,8) - \(\frac{3}{4}\)

h) \(1\frac{13}{15}\). 0,75 - (\(\frac{11}{20}\)+ 25%) : \(\frac{7}{3}\)

i) \(\frac{\left(\frac{1}{2}-0,75\right).\left(0,2-\frac{2}{5}\right)}{\frac{5}{9}-1\frac{1}{12}}\)

k) \(\frac{\frac{2}{3}+\frac{2}{7}-\frac{1}{14}}{-1-\frac{3}{7}+\frac{3}{28}}\)

bài 1:thực hiện phép tính

a,\(\frac{65}{91}\)+\(\frac{-33}{55}\) b,\(\frac{36}{-84}\)+\(\frac{100}{450}\) c,\(\frac{3}{7}\)+\(\frac{1}{2}\)-\(\frac{-3}{70}\) d,\(\frac{3}{5}\)+\(\frac{-1}{25}\)-\(\frac{-35}{100}\)

bài 2:tìm x,bt

a,x-\(\frac{-1}{5}\)=\(\frac{7}{25}\) b,x+\(\frac{5}{11}\)=\(\frac{4}{-9}\) c,\(\frac{5}{9}\)+\(\frac{x}{-1}\)=\(\frac{-1}{3}\) d,|x-4|=|\(\frac{-6}{7}\)|+\(\frac{3}{2}\)

bài 3:tính nhanh(hợp lí)

a,A=\(\frac{2}{15}\)+\(\frac{2}{35}\)+\(\frac{2}{63}\)+\(\frac{2}{99}\)+\(\frac{2}{143}\)

b,B=\(\frac{1}{21}\)+\(\frac{1}{77}\)+\(\frac{1}{165}\)+\(\frac{1}{285}\)

c,so sánh C=\(\frac{1}{11}\)+\(\frac{1}{12}\)+\(\frac{2}{12}\)+.................+\(\frac{1}{20}\)với \(\frac{1}{2}\)

mn giúp mk với ạ,mk đag cần gấp lắm,phải nộp luôn ạ,lm ơn

Tính hợp lý (nếu được)

\(a\) \(19\frac{5}{8}\)\(:\)\(1\frac{5}{7}\)\(-\) \(15\frac{5}{8}\) \(:\) \(\frac{12}{17}\)\(-\)\(1\frac{1}{3}\)

\(b\) \(\frac{2}{5}\)\(.\)\(\frac{1}{3}\)\(-\) \(\frac{2}{15}\)\(:\) \(\frac{1}{5}\)\(+\) \(\frac{3}{5}\)\(.\) \(\frac{1}{3}\)

\(c\)\(\left(3\frac{1}{3}+2,5\right):\left(3\frac{1}{6}-4\frac{1}{5}\right)-\frac{11}{31}\)

\(f\)\(\left(-2\right)^3.\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)

\(g\)\(\left(\frac{2}{5}\right)^2+5\frac{1}{2}.\left(4,5-2\right)+\frac{2^3}{\left(-4\right)}\)

\(h\)\(\frac{4}{9}.19\frac{1}{3}-\frac{4}{9}.39\frac{1}{3}\)

\(k\)\(125\%.\left(\frac{-1}{2}\right)^2:\left(1\frac{5}{16}-1,5\right)+2008^0\)

\(m\)\(F=\frac{1}{18}+\frac{1}{54}+\frac{1}{108}+...+\frac{1}{990}\)

Làm bao nhiêu cũng được nha, càng nhiều càng tốt

bài 1

a,\(\frac{x}{5}\)=\(\frac{2}{3}\)

b,\(\frac{x}{3}\)-\(\frac{1}{2}\)=\(\frac{1}{5}\)

c,\(\frac{x}{5}\)+\(\frac{1}{2}\)=\(\frac{6}{10}\)

d,\(\frac{x+3}{15}\)=\(\frac{1}{3}\)

e,\(\frac{x-12}{4}\)=\(\frac{1}{2}\)

h,\(\frac{4}{5}\)+x=\(\frac{2}{3}\)

i,\(\frac{3}{4}\)-x=\(\frac{1}{3}\)

k,\(\frac{-5}{6}\)-x=\(\frac{2}{3}\)

l,x-\(\frac{5}{9}\)=\(\frac{-2}{3}\)

m,\(\frac{1}{2}\)x+\(\frac{1}{2}\)=\(\frac{5}{2}\)

n,\(\frac{-2}{3}\)-\(\frac{1}{3}\)(2x-5)=\(\frac{3}{2}\)

p,(3x-1)(\(-\frac{1}{2}\)x+5)=0

q,\(3\frac{1}{3}\)+\(\frac{5}{6}\)x=\(3\frac{1}{2}\)

s,\(\frac{1}{2}\)-\(\frac{2}{3}\)x=\(\frac{7}{12}\)

t,\(\frac{3}{4}\)x+\(\frac{1}{5}\)=\(\frac{1}{6}\)

u,\(\frac{3}{8}\)-\(\frac{1}{6}\)x=\(\frac{1}{4}\)

mn ơi'-' xin hãy giúp mk với ạ>^<,mk cần rất gấp,mai nộp r ạ,mong mn giúp mk với ạ:(( huhuhu r mk tik cho:<<