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a: \(=7\cdot\dfrac{6}{7}-5+\dfrac{3\sqrt{2}}{2}=1+\dfrac{3}{2}\sqrt{2}\)
b: \(=-\dfrac{8}{7}-\dfrac{3}{5}\cdot\dfrac{5}{8}+\dfrac{1}{2}=\dfrac{-16+7}{14}-\dfrac{3}{8}=\dfrac{-9}{14}-\dfrac{3}{8}\)
\(=\dfrac{-72-42}{112}=\dfrac{-114}{112}=-\dfrac{57}{56}\)
c: \(=20\sqrt{5}-\dfrac{1}{4}\cdot\dfrac{4}{3}+\dfrac{3}{2}=20\sqrt{5}+\dfrac{3}{2}-\dfrac{1}{3}=20\sqrt{5}+\dfrac{7}{6}\)
Tính:
C = \(3\dfrac{1}{2}.\dfrac{4}{49}-\left[2,\left(4\right).2\dfrac{5}{11}\right]:\left(\dfrac{-42}{5}\right)\)
= \(\dfrac{7}{2}.\dfrac{4}{49}-\left[\left(2+0,\left(1\right).4\right).\dfrac{27}{5}\right].\dfrac{-5}{42}\)
= \(\dfrac{1.2}{1.7}-\left[\left(2+\dfrac{1.4}{9}\right).\dfrac{27}{5}\right].\dfrac{-5}{42}\)
= \(\dfrac{2}{7}-\left[\dfrac{18+4}{9}.\dfrac{27}{5}\right].\dfrac{-5}{42}\)
= \(\dfrac{2}{7}-\left[\dfrac{22.9}{3.5}\right].\dfrac{-5}{42}\)
= \(\dfrac{2}{7}-\dfrac{198}{15}.\dfrac{-5}{42}=\dfrac{2}{7}-\dfrac{11}{3}.\dfrac{-1}{7}\)
= \(\dfrac{2}{7}+\dfrac{11}{21}\) = \(\dfrac{6+11}{21}\) = \(\dfrac{17}{21}\)
a)\(\sqrt{1}\)+\(\sqrt{9}\)+\(\sqrt{25}\)+\(\sqrt{49}\)+\(\sqrt{81}\)
=1+3+5+7+9
=25
b)=\(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)+\(\dfrac{1}{6}\)+\(\dfrac{1}{4}\)
=\(\dfrac{6}{12}\)+\(\dfrac{4}{12}\)+\(\dfrac{2}{12}\)+\(\dfrac{3}{12}\)
=\(\dfrac{15}{12}\)
c) =0,2+0.3+0,4
= 0.9
d) =9-8+7
=8
j) =1,2-1,3+1.4
= (-0,1)+1,4
=1,4
g) \(\dfrac{2}{5}\)+\(\dfrac{5}{2}\)+\(\dfrac{9}{10}\)+\(\dfrac{3}{4}\)
= (\(\dfrac{4}{10}\)+\(\dfrac{15}{10}\)+\(\dfrac{9}{10}\))+\(\dfrac{3}{4}\)
= \(\dfrac{14}{5}\)+\(\dfrac{3}{4}\)
=\(\dfrac{56}{20}\)+\(\dfrac{15}{20}\)
= \(\dfrac{71}{20}\)
Nhớ tick cho mk nha~
a: \(=2\cdot\dfrac{5}{4}-3\cdot\dfrac{7}{6}+4\cdot\dfrac{9}{8}=\dfrac{5}{2}-\dfrac{7}{2}+\dfrac{9}{2}=\dfrac{7}{2}\)
b: \(=18-16\cdot\dfrac{1}{2}+\dfrac{1}{16}\cdot\dfrac{3}{4}\)
=10+3/64
=643/64
c: \(=\dfrac{2}{3}\cdot\dfrac{9}{4}-\dfrac{3}{4}\cdot\dfrac{8}{3}+\dfrac{7}{5}\cdot\dfrac{5}{14}=\dfrac{3}{2}-2+\dfrac{1}{2}=2-2=0\)
\(=\left[8+2\cdot3-7\cdot1.3+3\cdot\dfrac{5}{4}\right]:\sqrt{5+\dfrac{4}{3}}\)
\(=\dfrac{173}{20}\cdot\dfrac{\sqrt{57}}{3}=\dfrac{173\sqrt{57}}{60}\)
a) Có: \(\sqrt{9\cdot4}=\sqrt{36}=6\)
\(\sqrt{9}\cdot\sqrt{4}=3\cdot2=6\)
=> \(\sqrt{9\cdot4}=\sqrt{9}\cdot\sqrt{4}\)
b) \(\sqrt{16\cdot25}=\sqrt{400}=20\)
\(\sqrt{16}\cdot\sqrt{25}=4\cdot5=20\)
=> \(\sqrt{16\cdot25}=\sqrt{16}\cdot\sqrt{25}\)
c,d tương tự
ai đó giúp mk cái @Trần Việt Linh VS @Mai Phương aNH ơi
mn ơi, giúp vs
a\\(\sqrt{49}+\sqrt{4}=7+2=9\)
b\\(\sqrt{0,25}-\sqrt{0.01}=0.5-01=0.4\)
c\\(\sqrt{\dfrac{16}{25}}-\sqrt{\dfrac{1}{81}}=\dfrac{4}{5}-\dfrac{1}{9}=\dfrac{31}{45}\)
d\\(\sqrt{64}-\sqrt{16}+\sqrt{\left(-3\right)^2}=8-4+3=7\)
e\\(2-\sqrt{0,36}=2-0.6=1.4\)
Cảm ơn bạn!
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\(\sqrt{\dfrac{169}{64}}=\sqrt{\dfrac{13^2}{8^2}}=\dfrac{13}{8}\)
\(\dfrac{\sqrt{169}}{\sqrt{64}}=\dfrac{\sqrt{13^2}}{\sqrt{8^2}}=\dfrac{13}{8}\)
Vậy \(\sqrt{\dfrac{169}{64}}=\dfrac{\sqrt{169}}{\sqrt{64}}\)
Tương tự
Bị đao không hai căn bậc bằng nhau hết mà tính làm gì nhìn vô là biết bằng roy :V