1. Ta có thể viết số hữu tỉ \(\frac{-5}{16}\) dưới các dạng sau đây :
a) \(\frac{-5}{16}\) là tích của hai số hữu tỉ. Ví dụ : \(\frac{-5}{16}\) = \(\frac{-5}{2}\).\(\frac{1}{8}\)
b) \(\frac{-5}{16}\) là thương của hai số hữu tỉ. Ví dụ: \(\frac{-5}{16}\) = \(\frac{-5}{2}\):8
2. Tính:
a) \(\frac{-3}{4}.\frac{12}{-5}.\)\(\left(-\frac{25}{6}\right)\)
b) (\(-2\)).\(\frac{-38}{21}.\frac{-7}{4}.\left(-\frac{3}{8}\right)\)
c) \(\left(\frac{11}{12}:\frac{33}{16}\right).\frac{3}{5}\)
d) \(\frac{7}{23}.\left[\left(-\frac{8}{6}\right)-\frac{45}{18}\right]\)
3. Tính:
a) \(\left(\frac{-2}{3}+\frac{3}{7}\right):\frac{4}{5}+\left(\frac{-1}{3}+\frac{4}{7}\right):\frac{4}{5}\)
b) \(\frac{5}{9}:\left(\frac{1}{11}-\frac{5}{22}\right)+\frac{5}{9}:\left(\frac{1}{15}-\frac{2}{3}\right)\)
Tính bằng cách hợp lí nhất :
1/ \(\left(\frac{4}{9}-\frac{5}{11}\right):\frac{3}{10}+\left(\frac{3}{9}-\frac{9}{11}\right):\frac{3}{10}-\left(\frac{2}{9}-\frac{2}{8}\right).\frac{-10}{3}\)
2/ \(\frac{1}{2}.\frac{1}{-3}+\frac{1}{-3}.\frac{1}{4}+\frac{1}{4}.\frac{1}{-5}+\frac{1}{-5}.\frac{1}{6}\)
3/ \(-\frac{7}{4}\left(\frac{33}{12}+\frac{3333}{2020}+\frac{333333}{303030}+\frac{33333333}{42424242}\right)\)
1) Tính:
a) \(\frac{2}{3}-4.\left(\frac{1}{2}+\frac{3}{4}\right)\)
b)\(\left(-\frac{1}{3}+\frac{5}{6}\right).11-7\)
c) \(\frac{3}{11}.\frac{4}{15}+\frac{19}{15}.\frac{-3}{11}\)
Tính nhanh:
\(\frac{9-\frac{1}{11}-\frac{2}{12}-\frac{3}{13}-...-\frac{91}{101}}{\frac{1}{55}+\frac{1}{60}+\frac{1}{65}+...+\frac{1}{505}}\)
\(\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{5}{19}}{\left(\frac{1}{14}+\frac{1}{7}-\frac{-3}{5}\right).\frac{-4}{3}}\)
Giúp mik vs :< mai mik học r
1) Tìm x:
a) \(\frac{11}{12}-\frac{5}{12}.\left(\frac{2}{5}+x\right)=\frac{2}{3}\)
b) \(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
c) 2x.(x-\(\frac{1}{7}\))=0
d) (x + 1) . (x - 2) < 0
e) (x - 2) . ( x + \(\frac{2}{3}\) ) >0
Bài 1, Tìm x biết
a)\(\left|x\right|+\left|x+2\right|=0\)
b)\(\left|x\left(x^2-\frac{5}{4}\right)\right|=x\)
Tính nhanh:
\(\left(\frac{1}{2}-1\right)\).\(\left(\frac{1}{3}-1\right)\).\(\left(\frac{1}{4}-1\right)\).....\(\left(\frac{1}{1999}-1\right)\)
dấu . là dấu nhân nha
a)\(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)
b)\(\frac{3}{7}.19.\frac{1}{3}-\frac{3}{7}.33\frac{1}{3}\)
c)\(15\frac{1}{4}:(\frac{-5}{7})-25\frac{1}{4}:(\frac{-5}{7})\)
Cho :
\(A=\left[0,8.7+\left(0,8\right)^2\right]\left(1,25.7-\dfrac{4}{5}.1,25\right)+31,64\)
\(B=\dfrac{\left(1,09-0,29\right).\dfrac{5}{4}}{\left(18,9-16,65\right).\dfrac{8}{9}}\)
Hỏi A gấp mấy lần B ?