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15 tháng 9 2015

1x2+2x4+4x7+7x11+11x16+16x22=643

15 tháng 9 2015

toán với bóng đá giống chỗ nào

TOÁN \(\ne\) BÓNG ĐÁ

16 tháng 4 2022

Giải chi tiết cho mình nha

2/5 + 11/15 = 17/15
7/8 - 7/9 = 7/72
11/13 x 26/31 = 22/31
16/24 : 4 = 1/6
30 : 6/5 = 25
9/16 : 4 = 9/64
1/2 : 1/3 x 8/15 = 3/2 x 8/15 = 4/5

a: \(A=\dfrac{-7}{28}\cdot\dfrac{15}{25}=\dfrac{-1}{4}\cdot\dfrac{3}{5}=\dfrac{-3}{20}\)

b: \(B=\dfrac{-5\cdot7}{14\cdot\left(-3\right)}=\dfrac{35}{42}=\dfrac{5}{6}\)

c: \(C=\dfrac{-1}{5}-\dfrac{1}{5}\cdot\dfrac{3}{5}=\dfrac{-1}{5}-\dfrac{3}{25}=\dfrac{-8}{25}\)

d: \(D=\dfrac{-3}{4}-\dfrac{1}{4}=-1\)

e: \(E=\dfrac{-4}{5}\left(1-\dfrac{15}{16}\right)=\dfrac{-4}{5}\cdot\dfrac{1}{16}=\dfrac{-1}{20}\)

f: \(F=\dfrac{6-7}{4}\cdot\dfrac{4+12}{22}=\dfrac{-1}{4}\cdot\dfrac{8}{11}=\dfrac{-2}{11}\)

8 tháng 5 2022

a)\(=\dfrac{3}{3}+\dfrac{4}{3}=\dfrac{7}{3}\)

b)\(=\dfrac{5}{9}\times\dfrac{3}{2}=\dfrac{15}{18}=\dfrac{5}{6}\)

d)\(=\left(\dfrac{12}{8}-\dfrac{3}{8}\right)\times2=\dfrac{9}{8}\times2=\dfrac{18}{8}=\dfrac{9}{4}\)

c)\(=\dfrac{4}{3}-\dfrac{5}{6}=\dfrac{8}{6}-\dfrac{5}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)

8 tháng 5 2022

a) 1 + 4/3 = 7/3

b) 5/9 : 2/3 = 5/6

c ) 4/3 -1/3 x 5/2

= 1 x 5/2

= 5/2

d) ( 3/2 - 3/8) : 1/2

= 9/8 : 1/2

= 9/4

e) 15/16 : 3/8 x 3/4 

= 5/2 x 3/4

= 15/8

f) 7/19 x 1/3 x 7/19 x 2/3

= 7/19 x (1/3 x 2/3)

= 7/19 x 2/9

= 14/171

g) 3/5 x 8/27 x 25/3

= 3/5 x 25/3 x 8/27 

= 5 x 8/27

= 40/27

h) 1/5 + 4/11 + 4/5 + 7/11

= (1/5 + 4/5) + (4/11 + 7/11)

= 1 + 1

= 2

8 tháng 4 2017

minh ko biet nua moi lop 4 thoi

8 tháng 7 2017

a, 15 - 2 | x + \(\dfrac{1}{3}\)| = \(\dfrac{4}{7}\)

=>2| x + \(\dfrac{1}{3}\)| = 15 - \(\dfrac{4}{7}\)

=> 2 | x + \(\dfrac{1}{3}\)| =\(\dfrac{101}{7}\)

=> | x + \(\dfrac{1}{3}\)| = \(\dfrac{101}{14}\)

=> x+ \(\dfrac{1}{3}\)= \(\dfrac{101}{14}\) hoặc x +\(\dfrac{1}{3}\)= - \(\dfrac{101}{14}\)

+) x+\(\dfrac{1}{3}\)= \(\dfrac{101}{14}\)=> x = \(\dfrac{302}{3}\)

+) x + \(\dfrac{1}{3}\)= - \(\dfrac{101}{14}\)=> x =-\(\dfrac{317}{42}\)

Vậy ...........

b, \(\dfrac{13}{11}\).\(\dfrac{22}{26}\)-x2=\(\dfrac{7}{16}\)

=>1 -x2 = \(\dfrac{7}{16}\)

=> x2= \(\dfrac{9}{16}\)

=> x= \(\dfrac{3}{4}\)hoặc x = -\(\dfrac{3}{4}\)

Vậy ..................

8 tháng 7 2017

\(a,15-2\left|x+\dfrac{1}{3}\right|=\dfrac{4}{7}\)

\(2\left|x+\dfrac{1}{3}\right|=15-\dfrac{4}{7}\)

\(2\left|x+\dfrac{1}{3}\right|=\dfrac{101}{7}\)

\(\left|x+\dfrac{1}{3}\right|=\dfrac{101}{7}:2\)

\(\left|x+\dfrac{1}{3}\right|=\dfrac{101}{14}\)

\(\Rightarrow x+\dfrac{1}{3}=\dfrac{101}{14}\) hoặc \(x+\dfrac{1}{3}=-\dfrac{101}{14}\)

\(x=\dfrac{101}{14}-\dfrac{1}{3}\) \(x=-\dfrac{101}{14}-\dfrac{1}{3}\)

\(x=\dfrac{302}{3}\) \(x=-\dfrac{317}{42}\)

7 tháng 4 2020

\(a,\frac{x-22}{8}+\frac{x-21}{9}+\frac{x-20}{10}+\frac{x-19}{11}\)

7 tháng 4 2020

\(a,\frac{x-22}{8}+\frac{x-21}{9}+\frac{x-20}{10}+\frac{x-19}{11}=4\)

\(\Leftrightarrow\frac{x-22}{8}-1+\frac{x-21}{9}-1+\frac{x-20}{10}-1+\frac{x-19}{11}-1=0\)

\(\Leftrightarrow\frac{x-30}{8}+\frac{x-30}{9}+\frac{x-30}{10}+\frac{x-30}{11}=0\)

\(\Leftrightarrow\left(x-30\right)\left(\frac{1}{8}+\frac{1}{9}+\frac{1}{10}+\frac{1}{11}\right)=0\)

\(\Leftrightarrow\left(x-30\right)=0\)

\(\Leftrightarrow x=30\)