4/6 + 7/18 + 17/9 + 14/6 + 1/9

= 12/18 + 7/18 + 34/18 + 42/18 + 2/18

= ( 34/18 + 2/18 ) + ( 42/18 + 12/18 ) + 7/18

= 36/18 + 54/18 + 7/18

= 97/18

Trl:

\(\frac{4}{6}+\frac{7}{18}+\frac{17}{9}+\frac{14}{6}+\frac{1}{9}\)

\(=\frac{12}{18}+\frac{7}{18}+\frac{34}{18}+\frac{42}{18}+\frac{2}{18}\)

\(=\left(\frac{34}{18}+\frac{2}{18}\right)+\left(\frac{42}{18}+\frac{12}{18}\right)+\frac{7}{18}\)

\(=\left(\frac{36}{18}+\frac{54}{18}\right)+\frac{7}{18}\)

\(=\frac{90}{18}+\frac{7}{18}=\frac{97}{18}\)

#z

S no bỉe

bài2 \(x\times\dfrac{15}{16}-x\times\dfrac{4}{16}=2\) 

     \(x\times\dfrac{11}{16}=2\) 

     \(x=2:\dfrac{11}{16}\) 

    \(x=\dfrac{32}{11}\)

Bài 1 : 

 \(\dfrac{x}{16}\times\left(2017-1\right)=2\)

          \(\dfrac{x}{16}\times2016=2\)

                      \(\dfrac{x}{16}=\dfrac{2}{2016}\)

                         \(x=\dfrac{2}{2016}\times16\)

                         \(x=\dfrac{1}{63}\)

1- (5\(\dfrac{4}{9}\) +x+7\(\dfrac{7}{18}\)) : 15\(\dfrac{3}{4}\) = 0 

1- (\(\dfrac{49}{9}+x+\dfrac{133}{18}\)) : \(\dfrac{63}{4}=0\) 

 (\(\dfrac{49}{9}+\dfrac{133}{18}\)+\(x\) ) : \(\dfrac{63}{4}\) = 1 - 0 

       (\(\dfrac{77}{6}\) + \(x\) ) : \(\dfrac{63}{4}\) = 1

         \(\dfrac{77}{6}+x\)         = 1 x \(\dfrac{63}{4}\) 

          \(\dfrac{77}{6}\) + \(x\)          = \(\dfrac{63}{4}\)

                  \(x\)            = \(\dfrac{63}{4}\) - \(\dfrac{77}{6}\)

                  \(x=\) \(\dfrac{35}{12}\)

5/9 <1           ;              11/7 >1             ;             17/18<1             ;            1> 5/9                   ;         1<11/7    ;          1>17/18

tick cho mình nhé

c1 :ta thấy : 5 / 6 bé hơn 1 

              6 / 5lon hơn 1 nên 6/5 lớn hơn 5/6 

c2 5/6=5*5/6*5=25/30

     6/5=6*6/5*6=36/30 ma 25 < 36 nen 5/6 < 6/5

a, \(A=\frac{17^{18}+1}{17^{19}+1}< 1\)

\(A=\frac{17^{18}+1}{17^{19}+1}< \frac{17^{18}+1+16}{17^{19}+1+16}=\frac{17^{18}+17}{17^{19}+17}=\frac{17(17^{17}+1)}{17(17^{18}+1)}=B\)

\(\Rightarrow A< B\)

b, Tương tự câu a

a)Ta có : A =  \(\frac{17^{18}+1}{17^{19}+1}< \frac{17^{18}+1+16}{17^{19}+1+16}=\frac{17^{18}+17}{17^{19}+17}=\frac{17\left(17^{17}+1\right)}{17\left(17^{18}+1\right)}=\frac{17^{17}+1}{17^{18}+1}\)  = B

Vậy A < B

b) Làm tương tự như câu A

= 19 cách giải thì chờ OLM duyệt 

nhanhnhanh giup mk vs

Đặt A = \(\frac{\frac{1}{18}+\frac{2}{17}+....+\frac{18}{1}+18}{\frac{1}{18}+\frac{1}{17}+....+\frac{1}{1}}\)

Xét TS (tử số) của A ta có:

TS = \(\frac{1}{18}+\frac{2}{17}+...+\frac{18}{1}+18\)

\(TS=\left(\frac{1}{18}+1\right)+\left(\frac{2}{17}+1\right)+...+\left(\frac{18}{1}+1\right)\) (chia 18 ra 18 phần 1 đơn vị cộng lại cho mỗi phân số)

\(TS=\frac{19}{18}+\frac{19}{17}+...+\frac{19}{1}=19.\left(\frac{1}{18}+\frac{1}{17}+...+\frac{1}{1}\right)\)

Thay lại TS vào A ta có:

\(A=\frac{19.\left(\frac{1}{18}+\frac{1}{17}+...+\frac{1}{1}\right)}{\left(\frac{1}{18}+\frac{1}{17}+...+\frac{1}{1}\right)}=19\)

hai phân số bằng nhau

a)\(\frac{-5}{18}+\frac{32}{45}-\frac{9}{10}\)

\(=\frac{-25}{90}+\frac{64}{90}-\frac{81}{90}\)

\(=-\frac{42}{90}=-\frac{7}{15}\)

b)\(\frac{3}{4}-\left(-\frac{5}{8}\right)+\frac{9}{4}-\frac{3}{16}\)

\(=\frac{3}{4}+\frac{5}{8}+\frac{9}{4}-\frac{3}{16}\)

\(=\frac{12}{16}+\frac{10}{16}+\frac{36}{16}-\frac{3}{16}\)

\(=\frac{58}{16}=\frac{29}{8}\)

c) \(\frac{11}{125}-\frac{17}{18}-\frac{5}{7}+\frac{4}{9}+\frac{17}{14}=\frac{11}{125}\)

d) \(\frac{-2}{5}-\frac{3}{10}-\left(-\frac{1}{2}\right)\)

\(=-\frac{2}{5}-\frac{3}{10}+\frac{1}{2}\)

\(=-\frac{4}{10}-\frac{3}{10}+\frac{5}{10}\)

\(=-\frac{2}{10}=-\frac{1}{5}\)

1.hai gia tri tuyet doi, -

2.doi dau,-,-,+

3.tu va mau co uoc chung la 1 va -1

dai qua a