Giải bài 2 trang 30

Đề bài

Tính:

a) $5\frac{3}{4}.\frac{-8}{9}$

b) $3\frac{3}{4}:2\frac{1}{2}$

c) $\frac{-9}{5}:1,2$

d) ${\left(1,7\right)}^{2023}:{\left(1,7\right)}^{2021}$.

Lời giải chi tiết

a) $5\frac{3}{4}.\frac{-8}{9}=\frac{23}{4}.\frac{-8}{9}=\frac{-46}{9}$    

b) $3\frac{3}{4}:2\frac{1}{2}=\frac{15}{4}:\frac{5}{2}=\frac{15}{4}.\frac{2}{5}=\frac{3}{2}$

c) $\frac{-9}{5}:1,2=\frac{-9}{5}:\frac{12}{10}=\frac{-9}{5}.\frac{10}{12}=\frac{-3}{2}$

d) ${\left(1,7\right)}^{2023}:{\left(1,7\right)}^{2021}={\left(1,7\right)}^{2023-2021}={\left(1,7\right)}^2=2,89$.