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\(...=\dfrac{152}{10}-\dfrac{15}{9}+\dfrac{48}{10}-\dfrac{4}{19}=\dfrac{76}{5}-\dfrac{5}{3}+\dfrac{24}{5}-\dfrac{4}{19}\)
\(=\dfrac{76}{5}-\dfrac{5}{3}+\dfrac{24}{5}-\dfrac{4}{19}=\dfrac{76}{5}+\dfrac{24}{5}-\dfrac{5}{3}-\dfrac{4}{19}\)
\(=\dfrac{100}{5}-\dfrac{5}{3}-\dfrac{4}{19}=20-\dfrac{5}{3}-\dfrac{4}{19}=\dfrac{20.57-5.19-4.3}{57}=\dfrac{1033}{57}\)
a) \(\dfrac{-15}{-2023}=\dfrac{15}{2023}>0\)
\(\dfrac{3}{-4}< 0\)
\(\Rightarrow\dfrac{-15}{-2023}>\dfrac{3}{-4}\)
b) \(\dfrac{2014}{-2015}< 0\)
\(\dfrac{-5}{-7}=\dfrac{5}{7}>0\)
\(\Rightarrow\dfrac{2014}{-2015}< \dfrac{-5}{-7}\)
c) \(\dfrac{-4162}{3976}< 0\)
\(\dfrac{1}{2}>0\)
\(\Rightarrow\dfrac{-4162}{3976}< \dfrac{1}{2}\)
d) \(\dfrac{-2401}{7693}< 0\)
\(\dfrac{-4}{-7}=\dfrac{4}{7}>0\)
\(\Rightarrow\dfrac{-2401}{7693}< \dfrac{4}{7}\)
a: \(\dfrac{-15}{-2023}=\dfrac{15}{2023}>0\)
\(\dfrac{3}{-4}< 0\)
Do đó: \(\dfrac{-15}{-2023}>\dfrac{3}{-4}\)
b: \(\dfrac{2014}{-2015}< 0\)
\(\dfrac{-5}{-7}=\dfrac{5}{7}>0\)
Do đó: \(\dfrac{2014}{-2015}< \dfrac{-5}{-7}\)
c: \(-\dfrac{4162}{3976}< 0\)
\(0< \dfrac{1}{2}\)
Do đó: \(-\dfrac{4162}{3976}< \dfrac{1}{2}\)
d: \(\dfrac{-2401}{7693}< 0\)
\(0< \dfrac{4}{7}=\dfrac{-4}{-7}\)
Do đó: \(-\dfrac{2401}{7693}< \dfrac{-4}{-7}\)
e: -17<-4
=>\(\dfrac{-17}{2019}< \dfrac{-4}{2019}\)
=>\(\dfrac{17}{-2019}< \dfrac{-4}{2019}\)
g: \(\dfrac{-15}{-43}=\dfrac{15}{43}\)
mà 15>7
nên \(\dfrac{-15}{-43}=\dfrac{15}{43}>\dfrac{7}{43}\)
h: \(\dfrac{-15}{60}=\dfrac{-15\cdot3}{60\cdot3}=\dfrac{-45}{180}\)
\(\dfrac{-20}{45}=\dfrac{-20\cdot4}{45\cdot4}=\dfrac{-80}{180}\)
Ta có: -45>-80
=>\(-\dfrac{45}{180}>-\dfrac{80}{180}\)
=>\(-\dfrac{15}{60}>-\dfrac{20}{45}\)
k: \(\dfrac{11}{45}>0\)
\(0>-\dfrac{14}{30}\)
Do đó: \(\dfrac{11}{45}>-\dfrac{14}{30}\)
m: \(-\dfrac{17}{15}< -\dfrac{15}{15}=-1\)
\(-1< -\dfrac{5}{18}=\dfrac{5}{-18}\)
Do đó: \(\dfrac{-17}{15}< \dfrac{5}{-18}\)
n: \(-\dfrac{14}{42}< 0\)
\(0< \dfrac{-56}{-28}\)
Do đó: \(\dfrac{-14}{42}< \dfrac{-56}{-28}\)
b) Diện tích hình tròn là: \(4^2.3,14=50,24\left(cm^2\right).\)
Chu vi hình tròn là: \(4.2.3,14=25,12\left(cm\right).\)
a) Ta có hình vẽ sau:
b) Diện tích hình tròn là:
4 . 4 . 3,14 = 50,24 (cm2)
Chu vi hình tròn là:
4 . 2 . 3,14 = 25,12 (cm)
1) \(5\cdot2^2-18:3=5\cdot4-6=20-6=14\)
2) \(29\cdot75+25\cdot29-250=29\cdot\left(75+25\right)-250=29\cdot100-250=2900-250=2650\)
3) \(561+216+139+154=\left(561+139\right)+\left(216+154\right)=700+370=1070\)
4) \(91:\left\{350:\left[450-\left(4\cdot5^3-2^2\cdot25\right)\right]\right\}=91:\left\{350:\left[450-\left(4\cdot125-4\cdot25\right)\right]\right\}\)
\(=91:\left[350:\left(450-400\right)\right]=91:\left(350:50\right)=91:7=13\)
Câu 2:
1: \(\Leftrightarrow x\cdot\dfrac{7}{2}=\dfrac{9}{2}+3=\dfrac{15}{2}\)
hay x=15/7
2: \(\Leftrightarrow x=\dfrac{5}{2}\cdot\dfrac{8}{5}=4\)
3: \(\Leftrightarrow x=\dfrac{-11\cdot10}{5}=-11\cdot2=-22\)
4: =>2x=90
hay x=45
a: Ư(8)={1;2;4;8}
Ư(12)={1;2;3;4;6;12}
UC(8;12)={1;2;4}
b: B(16)={0;16;32;...}
B(24)={0;24;48;...}
BC(16,24)={0;48;96;...}