1.So sánh
a.\(\dfrac{21}{52}\)và\(\dfrac{-213}{523}\)
b.\(\dfrac{22}{35}\)và\(\dfrac{103}{17}\)
c.\(\dfrac{-2525}{4949}\)và\(\dfrac{-131313}{373737}\)
a)Vì \(\dfrac{21}{52}>0\); \(\dfrac{-213}{523}< 0\)
\(\Rightarrow\)\(\dfrac{21}{52}>\dfrac{-213}{523}\)
b)Ta có :\(\dfrac{22}{35}< 1\) ;\(\dfrac{103}{17}>1\)
\(\Rightarrow\)\(\dfrac{22}{35}< \dfrac{103}{17}\)
c)Ta có :\(\dfrac{-2525}{4949}=\dfrac{-25}{49}\) ;\(\dfrac{-131313}{373737}=\dfrac{-13}{37}\)
Lại có :\(\dfrac{25}{49}>\dfrac{25}{50}=\dfrac{1}{2}\) hay \(\dfrac{-25}{49}< \dfrac{-25}{50}=\dfrac{-1}{2}\)(1)
và \(\dfrac{13}{37}< \dfrac{13}{26}=\dfrac{1}{2}\) hay \(\dfrac{-13}{37}>\dfrac{-13}{26}=\dfrac{-1}{2}\) (2)
Từ (1) và (2) \(\Rightarrow\)\(\dfrac{-2525}{4949}< \dfrac{-131313}{373737}\)
Tính nhanh
1/3 - 3/4 - 3/5 + 1/64 - 2/9 - 1/36 + 1/15
1/5-3/7+5/9-2/11+7/13-9/16-7/13+2/11-5/9+3/7-1/5
1) Tính : a) \(\left(\dfrac{-5}{11}\right)\) .\(\dfrac{7}{15}\) . \(\left(\dfrac{11}{-5}\right)\) .(-30) b) \(\left(\dfrac{11}{12}:\dfrac{33}{16}\right)\). \(\dfrac{3}{5}\) c) \(\dfrac{-7}{15}\).\(\dfrac{5}{8}\).\(\dfrac{15}{-7}\). (-16) d) \(\left(-\dfrac{1}{2}\right)\). \(3\dfrac{1}{5}\)+ \(\left(-\dfrac{1}{2}\right)\).\(-2\dfrac{1}{5}\)
Tính nhanh:
\(\left(\dfrac{-3}{7}+\dfrac{4}{11}\right):\dfrac{7}{11}+\left(\dfrac{-4}{7}+\dfrac{7}{11}\right):\dfrac{7}{11}\)
Các bn giúp mk vs nha
\(\dfrac{6^3+3\cdot6^2+3^3}{-13}\)
1.\(\dfrac{-1}{4}-\dfrac{3}{4}:x=\dfrac{-11}{36}\)
2.\(\left(-1\dfrac{1}{5}+x\right):\left(-3\dfrac{3}{5}\right)=\dfrac{-7}{4}+\dfrac{1}{4}:\dfrac{1}{8}\)
a) \(\dfrac{-2}{7}.\dfrac{21}{8}\) b) 0.24.\(\dfrac{-15}{4}\)
c) (-2).\(\left(\dfrac{-7}{12}\right)\) d) \(\left(\dfrac{-3}{25}\right):6\)
Tìm a,b biết
a+b=a*b=a/b
Cho tam giác ABC cân tại A.Gọi M là trung điểm cạnh BC.
a,C/m tam giác ABM=tam giác ACM
b,Từ M vẽ MH vuông góc AB và MK vuông góc AC.C/m BH=CK
C,Từ B vẽ BP vuông góc AC,BP cắt MH tại I.C/m tam giác IBM cân
16.2x.(x-1/7)=0
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