\(\dfrac{-9}{7^4}>\dfrac{-9}{7^9}do7^4< 7^9\)
Vì \(7^4< 7^9\) nên \(\dfrac{-9}{7^4}>\dfrac{-9}{7^9}\)
Vậy \(\dfrac{-9}{7^4}>\dfrac{-9}{7^9}\)
BT1: Tính nhanh
1) \(\left(\dfrac{-4}{9}+\dfrac{3}{7}\right):1\dfrac{1}{15}+\left(\dfrac{4}{7}-\dfrac{5}{9}\right):1\dfrac{1}{15}\)
2) \(3\dfrac{2}{9}.15\dfrac{4}{7}-3\dfrac{2}{9}.8\dfrac{1}{7}+3\dfrac{2}{9}.\dfrac{15}{7}-3\dfrac{2}{9}.\dfrac{1}{7}\)
1, Tính
\(-2\dfrac{1}{4}.\left(3\dfrac{5}{12}-1\dfrac{2}{9}\right)\)
\(\left(-25\%+0,75+\dfrac{7}{12}\right):\left(-2\dfrac{1}{8}\right)\)
2, Tính nhanh
\(\dfrac{4}{9}.19\dfrac{1}{3}-\dfrac{4}{9}.39\dfrac{1}{3}\) | \(19\dfrac{5}{8}:\dfrac{7}{12}-15\dfrac{1}{4}.\dfrac{12}{7}\)
\(\dfrac{-5}{7}.\dfrac{5}{11}+\dfrac{-5}{7}.\dfrac{2}{11}-\dfrac{5}{7}:\dfrac{11}{14}\) | \(\dfrac{4}{7}.\dfrac{89}{5}-\dfrac{4}{5}.\dfrac{82}{7}\)
\(\dfrac{5}{7}.\dfrac{-4}{19}+\dfrac{-15}{7}.\dfrac{5}{19}\) | \(8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\)
- Giải hộ với ạ, mấy anh, chị lớp 7,8 cũng được huhu :(( sáng mai nộp đề cương rồi. Làm ơn đi a
Muốn gì cũng hậu tạ :>
Tính:
\(\dfrac{\dfrac{1}{3}-\dfrac{1}{5}-\dfrac{1}{7}}{\dfrac{2}{3}-\dfrac{2}{5}-\dfrac{2}{7}}\) + \(\dfrac{\dfrac{4}{7}-\dfrac{4}{9}+\dfrac{4}{11}}{\dfrac{3}{7}-\dfrac{1}{3}+\dfrac{9}{11}}\)=?
\(B=\left(7\dfrac{4}{9}+3\dfrac{8}{13}\right)-5\dfrac{4}{9}\)
\(C=\dfrac{-2}{7}.\dfrac{5}{11}+\dfrac{-2}{7}.\dfrac{6}{11}+5\dfrac{4}{7}\)
\(D=0,7.1\dfrac{3}{5}.30.0,375.\dfrac{4}{7}\)
A= \(8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\)
B=\(\left(10\dfrac{2}{9}+2\dfrac{3}{5}\right)-6\dfrac{2}{9}\)
- Giúp con ngu lâu dốt bền môn toán này với :(
BT2: Tính nhanh
1) \(\dfrac{5}{6}-\dfrac{6}{7}+\dfrac{7}{8}-\dfrac{8}{9}+\dfrac{10}{9}-\dfrac{5}{6}+\dfrac{6}{7}-\dfrac{7}{8}+\dfrac{8}{9}\)
2) \(\dfrac{1}{13}+\dfrac{16}{7}+\dfrac{3}{105}-\dfrac{9}{7}-\dfrac{-12}{13}\)
\(B=\left(7\dfrac{4}{9}+3\dfrac{8}{13}\right)-5\dfrac{4}{9}\)
\(D=0,7.1\dfrac{3}{5}.30.0,375.\dfrac{4}{7}\)
BT3: Tìm x, biết
9) \(\dfrac{x}{9}< \dfrac{7}{x}< \dfrac{x}{6}\) ( với x \(\in\) N*
10) \(\dfrac{7}{x}< \dfrac{x}{4}< \dfrac{10}{x}\) ( với x \(\in\) N*)
Tính nhanh:
11) \(\dfrac{5}{7}\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{4}{7}\right)+\left(\dfrac{1}{3}-\dfrac{1}{2}-\dfrac{4}{7}\right):\dfrac{7}{5}\)
12)\(\dfrac{43}{5}\left(\dfrac{17}{3}-\dfrac{16}{9}+2\right)-\dfrac{43}{5}\left(\dfrac{17}{3}-\dfrac{16}{9}\right)\)
