Bài 1:

a) $\frac{2}{3}-\frac{7}{6}+\frac{3}{4}=$ $\frac{8}{12}-\frac{14}{12}+\frac{9}{12}=$ $\frac{3}{12}$ = $\frac{1}{4}$ 

b) $(7\frac{4}{5}-1\frac{9}{10})-5\frac{4}{5}=$ $\frac{39}{5}-\frac{19}{10}-$ $\frac{29}{5}=$ $\frac{10}{5}-\frac{19}{10}=$ $\frac{20}{10}-$ $\frac{19}{10}=$ $\frac{1}{10}$ 

c) $\frac{-11}{23}.\frac{2}{5}+$ $\frac{-12}{23}.$ $\frac{2}{5}-\frac{3}{5}=$ $\frac{2}{5}(\frac{-11}{23}+\frac{-12}{23})-\frac{3}{5}=$ $\frac{2}{5}.\frac{-23}{23}-\frac{3}{5}=$ $\frac{2}{5}.(-1)-\frac{3}{5}=$ $\frac{-2}{5}-\frac{3}{5}=$ $\frac{-5}{5}=-1$ 

d) $(-\frac{1}{2})^{3}:|-1\frac{3}{8}|-(-2)^3.75$% =$(-\frac{1}{8}):\frac{11}{8}-(-8).\frac{3}{4}=$$\frac{-1}{8}.\frac{8}{11}-(-6)=$$\frac{-1}{11}+6=$$\frac{-1}{11}+\frac{66}{11}=$$\frac{65}{11}$ 

Bài 2:

a) $-\frac{2}{3}+\frac{3}{4}x=-\frac{5}{6}$

<=> $\frac{3}{4}x=-\frac{5}{6}+\frac{2}{3}$

<=> $\frac{3}{4}x=\frac{-5}{6}+\frac{4}{6}$

<=> $\frac{3}{4}x=\frac{-1}{6}$

<=> $x=\frac{-1}{6}.\frac{4}{3}$

<=> $x=\frac{-2}{9}$ 

b) $\frac{2}{25}:(2x-1)=(\frac{-1}{5})^2$

<=> $\frac{2}{25}:(2x-1)=\frac{1}{25}$

<=> $2x-1=\frac{1}{25}.\frac{25}{2}$ <=> $2x-1=\frac{1}{2}$

<=> $2x=\frac{1}{2}+1$

<=> $2x=\frac{1}{2}+\frac{2}{2}$

<=> $2x=\frac{3}{2}$

<=> $x=\frac{3}{2}.\frac{1}{2}$

<=> $x=\frac{3}{4}$ 

Chúc bạn học tốt ^-^

B1:

a) ($\frac{2}{3}$ -$\frac{7}{6}$)+$\frac{3}{4}$  

=$\frac{-1}{2}$ +$\frac{3}{4}$ 

=$\frac{1}{4}$ 
b)=($\frac{47}{10}$ -5$\frac{4}{5}$ 

=$\frac{7}{10}$