a) \(\dfrac{3}{8}+\dfrac{15}{-25}+\dfrac{3}{5}\)

\(=\dfrac{-9}{40}+\dfrac{3}{5}\)

\(=\dfrac{3}{8}\)

b) \(\dfrac{-5}{18}+\dfrac{23}{45}-\dfrac{9}{10}\)

\(=\dfrac{7}{30}-\dfrac{9}{10}\)

\(=\dfrac{-2}{3}\)

c) \(\dfrac{-5}{12}+\dfrac{15}{18}-2,25\)

\(=\dfrac{5}{12}-2,25\)

\(=\dfrac{-11}{6}\)

d) \(\dfrac{5}{6}+\dfrac{2}{3}-0,5\)

\(=\dfrac{3}{2}-0,5\)

\(=1\)

tick cho mink nhé bn ✔

1/2 và 5/4

1/2<1

5/4>1

\(\Rightarrow\)1/2 < 5/4

1/3 Và 4/9

1/3 = 3/9

Vì 3/9< 4/9 nên 1/3 < 4/95

3/4 = 15/20

7/10= 14/20

Vì 15/20 > 14/20 nên 3/4 > 7/10

22/23 Và 22/33

22/23 và 22/33 có tử chung là 22 mà 23<33\(\Rightarrow\)22/23>22/33

10/9 và 10/7

10/9 và 10/7 có tử chung là 10 mà 9 >3\(\Rightarrow\)10/7 > 10/9

10/3 và 10/7

10/3 và 10/7 có tử chung là 10 mà 3 < \(\Rightarrow\)10/3 > 10/7

tk mình nha !

1/2 < 5/4 , 1/3 < 4/9 , 3/4 > 7/10 , 22/23 = 22/23 , 22/23 < 10/9 , 10/3 > 10/7

\(=-\dfrac{3}{4}+3-\dfrac{1}{4}-\dfrac{9}{4}+\dfrac{9}{2}=-\dfrac{13}{4}+3+\dfrac{9}{2}=\dfrac{17}{4}\)

   \(-\dfrac{3}{4}+\left(3-\dfrac{1}{4}\right)-\left(2,25-\dfrac{9}{2}\right)\)

= \(-1+3-\left(\dfrac{9}{4}-\dfrac{9}{2}\right)\)

= \(2+\dfrac{9}{4}=\dfrac{17}{4}\)

\(-\dfrac{3}{4}+\left(3-\dfrac{1}{4}\right)-\left(2,25-\dfrac{9}{2}\right)=-\dfrac{3}{4}+\dfrac{11}{4}-1,8=2-1,8=0,2\)

Giải:

a) \(\left(9\dfrac{4}{9}+5\dfrac{2}{3}\right)-5\dfrac{1}{2}\) 

\(=\left(\dfrac{85}{9}+\dfrac{17}{3}\right)-\dfrac{11}{2}\) 

\(=\dfrac{136}{9}-\dfrac{11}{2}\) 

\(=\dfrac{173}{18}\) 

b) \(\dfrac{13}{9}.\dfrac{15}{4}-\dfrac{13}{9}.\dfrac{7}{4}-\dfrac{13}{9}.\dfrac{5}{4}\) 

\(=\dfrac{13}{9}.\left(\dfrac{15}{4}-\dfrac{7}{4}-\dfrac{5}{4}\right)\) 

\(=\dfrac{13}{9}.\dfrac{3}{4}\) 

\(=\dfrac{13}{12}\) 

c) \(\dfrac{2}{3}+\dfrac{5}{8}-\dfrac{-1}{3}+0,375\) 

\(=\left(\dfrac{2}{3}-\dfrac{-1}{3}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)\) 

\(=1+1\) 

\(=2\)

d) \(75\%-3\dfrac{1}{2}+1,5:\dfrac{10}{7}\) 

\(=\dfrac{3}{4}+\dfrac{7}{2}+\dfrac{3}{2}:\dfrac{10}{7}\) 

\(=\dfrac{3}{4}+\dfrac{7}{2}+\dfrac{21}{20}\) 

\(=\dfrac{53}{10}\) 

e) \(1\dfrac{13}{15}.\left(0,5\right)^2.3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right):1\dfrac{23}{24}\) 

\(=\dfrac{28}{15}.\dfrac{1}{4}.3+\left(\dfrac{8}{15}-\dfrac{79}{60}\right):\dfrac{47}{24}\) 

\(=\dfrac{7}{5}+\dfrac{-47}{60}:\dfrac{47}{24}\) 

\(=\dfrac{7}{5}+\dfrac{-2}{5}\) 

\(=1\)

Giải:

a) \(11\dfrac{3}{4}.\left(6\dfrac{5}{6}-4\dfrac{1}{2}+1\dfrac{2}{3}\right)\) 

\(=\dfrac{47}{4}.\left(\dfrac{41}{6}-\dfrac{9}{2}+\dfrac{5}{3}\right)\) 

\(=\dfrac{47}{4}.4\) 

\(=47\) 

b) \(\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\) 

\(=\left(\dfrac{47}{8}-\dfrac{9}{4}-\dfrac{1}{2}\right):\dfrac{75}{26}\) 

\(=\dfrac{25}{8}:\dfrac{75}{26}\) 

\(=\dfrac{13}{12}\)

c) \(\left(17\dfrac{13}{15}-3\dfrac{3}{7}\right)-\left(2\dfrac{12}{15}-4\right)\) 

\(=\dfrac{268}{15}-\dfrac{24}{7}-\dfrac{14}{5}+4\) 

\(=\left(\dfrac{268}{15}-\dfrac{14}{5}\right)+\left(\dfrac{-24}{7}+4\right)\) 

\(=\dfrac{226}{15}+\dfrac{4}{7}\) 

\(=\dfrac{1642}{105}\) 

d) \(2\dfrac{2}{3}.\left(\dfrac{-4}{5}.0,375.-10.\dfrac{-15}{24}\right)\) 

\(=\dfrac{8}{3}.\left(\dfrac{-4}{5}.\dfrac{3}{8}.-10.\dfrac{-5}{8}\right)\) 

\(=\left(\dfrac{8}{3}.\dfrac{3}{8}\right).\left(\dfrac{-4}{5}.\dfrac{-5}{8}.-10\right)\) 

\(=1.-5\) 

\(=-5\) 

Chúc bạn học tốt!

a) \(\frac{-1}{2}.3x+\frac{3}{4}=-2,25\)

\(\frac{-1}{2}.3x+\frac{3}{4}=\frac{9}{4}\)

\(\frac{-1}{2}.3x=\frac{9}{4}-\frac{3}{4}\)

\(\frac{-1}{2}.3x=\frac{6}{4}=\frac{3}{2}\)

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

\(3x=-3\)

\(x=\left(-3\right):3\)

\(x=-1\)

b) \(13-3\left|x-2\right|=10\)

\(3\left|x-2\right|=13-10\)

\(3\left|x-2\right|=3\)

\(\left|x-2\right|=3:3\)

\(\left|x-2\right|=1\)

\(\Rightarrow\hept{\begin{cases}\left|x-2\right|=1\\\left|x-2\right|=-1\end{cases}\Rightarrow\hept{\begin{cases}x=3\\x=1\end{cases}}}\)

\(B=\left(8-2,25+\dfrac{2}{7}\right)-\left(-6-\dfrac{3}{7}+1\dfrac{1}{4}\right)-\left(3+0,5-1\dfrac{2}{7}\right)\\ B=8-\dfrac{9}{4}+\dfrac{2}{7}+6+\dfrac{3}{7}-\dfrac{5}{4}-3-\dfrac{1}{2}+\dfrac{9}{7}\\ B=\left(8+6-3\right)+\left(-\dfrac{9}{4}-\dfrac{5}{4}\right)+\left(\dfrac{2}{7}+\dfrac{3}{7}+\dfrac{9}{7}\right)-\dfrac{1}{2}\)

\(B=11-\dfrac{7}{2}+2-\dfrac{1}{2}\\ B=\left(11+2\right)+\left(-\dfrac{7}{2}-\dfrac{1}{2}\right)\\ B=13-4\\ B=9.\)