a) ta co:
1/18<x/12<y/9<1/4
=>2/36<x.3/36<y.4/36<9/36
=>x.3thuộc{3;6};y.4thuộc{4;8}
=>x thuộc{1;2};y thuộc{1:2}
b) ta co
7/8<x/40<9/10
=>70/80<x.2/40<72/80
=>x.2 =71
=>x=71/2
Bài 1; Tính
a)\(\left(\dfrac{5}{18}-\dfrac{7}{24}+\dfrac{1}{9}\right):\dfrac{7}{18}\)
b)\(\left(\dfrac{7}{20}-\dfrac{5}{16}+\dfrac{3}{40}\right):\left(\dfrac{4}{15}-\dfrac{3}{10}+\dfrac{1}{12}\right)\)
Bài 2:Tìm x
a)\(\dfrac{3}{10}-x=\dfrac{5}{6}-\dfrac{2}{15}\)
b)\(\dfrac{-5}{8}+x=\dfrac{4}{9}-\dfrac{7}{1}\)
c)\(\dfrac{2}{x-3}=\dfrac{x-3}{18}\)
Giúp mk zới m.n mk gấp lắm mk tick cho
Tính:
a. 75% - 1\(\dfrac{1}{2}\).\(\dfrac{4}{3}\) + 1,5 : \(\dfrac{-9}{4}\)- (-\(\dfrac{1}{2}\))2
b. \(\dfrac{-4}{9}\).\(\dfrac{6}{13}\) + 7\(\dfrac{4}{9}\) - \(\dfrac{4}{9}:\dfrac{13}{7}-5\dfrac{4}{9}\) - 2
Tìm x:
a. \(\dfrac{7}{12}-\left(x+\dfrac{7}{10}\right):\dfrac{6}{5}=\dfrac{-5}{4}\)
b. x \(\in\) Z, -1 \(\le\) \(\dfrac{x}{5}\) < 0
*Lm nhanh nha, mk cần gấp
Cho A=\(\dfrac{\dfrac{-5}{8}x\dfrac{3}{7}+\dfrac{3}{7}x\dfrac{3}{4}+\dfrac{1}{7}x\dfrac{1}{2}+\dfrac{15}{8}}{a+\dfrac{5}{6}-\left(\dfrac{-1}{3}\right)}\)
a) Rút gọn A?
b) Tính A khi a=75%
c) Tìm a để A=50%
d) Tìm a thuộc Z để A là số nguyên.
e) Với a= bao nhiêu để A có giá trị bằng với giá trj của biểu thức:
B=\(\dfrac{\dfrac{2}{3}x\dfrac{15}{6}+\left(-0,5\right)^3}{\dfrac{1}{9}x\left(6\right)^2-5\dfrac{1}{3}}\)
Dấu x là dấu nhân nhé!
Giúp mk với mk cần lắm! AI nhanh mk tick cho! Hứa và đảm bảo!
Cảm ơn các bn trước nhé!
Tìm x :
\(\dfrac{1}{3}x-\dfrac{1}{2}=\dfrac{3}{4}x+\dfrac{1}{15}\)
\(\left(x-\dfrac{2}{9}\right)^3=\left(\dfrac{2}{3}\right)^6\)
Mk đang cần gấp lắm xin hãy giúp mk làm ơn
Bài 1: Tìm x biết: a) \(\dfrac{2}{5}\) . x - \(\dfrac{1}{4}\) = \(\dfrac{1}{10}\) b) \(\dfrac{3}{5}\) = \(\dfrac{24}{x}\) c) (2.x - 3)\(^2\) = 16
Bài 2: Thực hiện các phép tính:
a)25% - 4\(\dfrac{2}{5}\) + 0,3 :\(\dfrac{6}{5}\) b) (\(\dfrac{1}{6}\) - \(\dfrac{1}{5^2}\) . 5 + \(\dfrac{1}{30}\) ) . (\(\dfrac{2011}{2010}\) + \(\dfrac{2010}{1009}\) + \(\dfrac{2009}{2008}\))
Bài 3: Thực hiện tính nhanh:
a)\(\dfrac{4}{19}.\dfrac{-3}{7}+\dfrac{-3}{7}.\dfrac{15}{19}+\dfrac{5}{7}\) b) \(7\dfrac{5}{9}-\left(2\dfrac{3}{4}+3\dfrac{5}{9}\right)\)
Bài 5: Tính tổng sau:
\(\dfrac{4}{12.14}+\dfrac{4}{14.16}+\dfrac{4}{16.18}+...+\dfrac{4}{58.60}\)
HELP ME!! Mk đang cần gấp. Ai nhanh, đầy đủ mk tick cho!
Bài 1: Tìm x, biết:
a, \(\left(x+\dfrac{1}{4}-\dfrac{1}{3}\right):\left(2+\dfrac{1}{6}-\dfrac{1}{4}\right)=\dfrac{7}{46}\)
b, \(\dfrac{13}{15}-\left(\dfrac{13}{21}+x\right).\dfrac{7}{12}=\dfrac{7}{10}\)
Bài 2: Thực hiện phép tính:
a, \(\left(2\dfrac{5}{6}+1\dfrac{4}{9}\right):\left(10\dfrac{1}{12}-9\dfrac{1}{2}\right)\)
b, 1\(\dfrac{5}{18}-\dfrac{5}{18}.\left(\dfrac{1}{15}+1\dfrac{1}{12}\right)\)
c, \(-\dfrac{1}{7}.\left(9\dfrac{1}{2}-8,75\right):\dfrac{2}{7}+0,625:1\dfrac{2}{3}\)
Tìm x biết
\(\dfrac{x-1}{12}+\dfrac{x-1}{20}+\dfrac{x-1}{30}+\dfrac{x-1}{42}+\dfrac{x-1}{56}+\dfrac{x-1}{72}=\dfrac{16}{9}\)
Help me!! Mk đang cần gấp
Bài 1: Tính
a) ( \(\dfrac{-3}{4}\)+ \(\dfrac{2}{5}\)) : \(\dfrac{3}{7}\)+ ( \(\dfrac{3}{5}\) + \(\dfrac{-9}{4}\)) :\(\dfrac{3}{7}\)
b) \(\dfrac{7}{8}\): ( \(\dfrac{2}{9}\)- \(\dfrac{1}{18}\)) + \(\dfrac{7}{8}\) : ( \(\dfrac{1}{36}\) - \(\dfrac{5}{12}\))
Cần gấp 
Tìm x:
a)\(2016x+\left(\dfrac{7}{12}+\dfrac{4}{21}+\dfrac{2}{24}+\dfrac{11}{30}+\dfrac{3}{40}+\dfrac{15}{56}\right)-\left(\dfrac{2}{3}+\dfrac{2}{4}+\dfrac{2}{5}\right)=0\)
b\(\dfrac{2x-1}{x+2015}-\dfrac{4025}{x+2017}=\dfrac{x-2014}{2x-4036}-\dfrac{x-2013}{2x-4030}\) (x thuộc N)
c)\(\left(1+\dfrac{1}{1.3}\right)\left(1+\dfrac{1}{2.4}\right)\left(1+\dfrac{1}{3.5}\right)...\left(1+\dfrac{1}{x\left(x+2\right)}\right)=\dfrac{4016}{2007}\)
AI GIÚP MK VỚI MK TICK CHO 
