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a) \(\sqrt{0,09.64}=\sqrt{\left(0,3\right)^2.8^2}=0,3.8=2,4\)
b) \(\sqrt{2^4.\left(-7\right)^2}=\sqrt{\left(2^2\right)^2.\left(-7\right)^2}=2^2.\left|-7\right|=7.4=28\)
c) \(\sqrt{12,1.360}=\sqrt{12,1.10.36}=\sqrt{121.36}=\sqrt{11^2.6^2}=11.6=66\)
d) \(\sqrt{2^2.3^4}=\sqrt{2^2.\left(3^2\right)^2}=2.3^2=9.2=18\)
a) \(\sqrt{0,09\cdot64}=\sqrt{0,09}\cdot\sqrt{64}=0,3\cdot8=2,4\)
b) \(\sqrt{2^4\cdot\left(-7\right)^2}=\sqrt{2^4}\cdot\sqrt{\left(-7\right)^2}=2^2\cdot7=4\cdot7=28\)
c) \(\sqrt{12,1\cdot360}=\sqrt{12,1\cdot10\cdot36}=\sqrt{121\cdot36}=\sqrt{121}\cdot\sqrt{36}=11\cdot6=66\)
d) \(\sqrt{2^2\cdot3^4}=\sqrt{2^2}\cdot\sqrt{3^4}=2\cdot3^2=2\cdot9=18\)
a)\(\sqrt{45.80}=\sqrt{9.400}=\sqrt{9}.\sqrt{400}=3.20=60\)
b) \(\sqrt{75.48}=\sqrt{25.3.16.3}=\sqrt{5^2.3^2.4^2}=5.4.3=60\)
c)\(\sqrt{90.6,4}=\sqrt{10.9.4.1,6}=\sqrt{4^2.3^2.2^2}=4.3.2=24\)
d) \(\sqrt{2,5.14,4}=\sqrt{\dfrac{25}{10}.\dfrac{144}{10}}=\sqrt{\dfrac{25.144}{100}}=\sqrt{\left(\dfrac{5.12}{10}\right)^2}=\dfrac{5.12}{10}=6\)
a) \(\sqrt{45.80}=\sqrt{9.400}=\sqrt{9}.\sqrt{400}=3.20=60\)
b)\(\sqrt{75.48}=\sqrt{25.3.3.16}=5.3.4=60\)
c)\(\sqrt{90.6,4}=\sqrt{9.64}=3.8=24\)
d)\(\sqrt{2,5.14,4}=\sqrt{\dfrac{25}{10}.\dfrac{144}{10}}=\sqrt{\dfrac{25.144}{100}=\dfrac{5.12}{10}=\dfrac{60}{10}=6}\)
Áp dụng quy tắc khai phương một thương, hãy tính :
a) 9169−−−−√ = \(\sqrt{\dfrac{3^2}{13^2}}\) = \(\left|\dfrac{3}{13}\right|\) = \(\dfrac{3}{13}\)
b) 25144−−−−√ = \(\sqrt{\dfrac{5^2}{12^2}}\) = \(\left|\dfrac{5}{12}\right|\) = \(\dfrac{5}{12}\)
c) 1916−−−−√ = \(\sqrt{\dfrac{25}{16}}\) = \(\sqrt{\dfrac{5^2}{4^2}}\) = \(\left|\dfrac{5}{4}\right|\) = \(\dfrac{5}{4}\)
d) 2781−−−−√ = \(\sqrt{\dfrac{169}{81}}\) = \(\sqrt{\dfrac{13^2}{9^2}}\) = \(\left|\dfrac{13}{9}\right|\) = \(\dfrac{13}{9}\)
\(\frac{3\sqrt{128}}{\sqrt{2}}=\frac{\sqrt{9.128}}{\sqrt{2}}=\sqrt{\frac{1152}{2}}=\sqrt{576}=24\)
a)\(\sqrt{75\cdot48}=\sqrt{25\cdot3\cdot48}=\sqrt{25\cdot144}=\sqrt{25}\cdot\sqrt{144}=5\cdot12=60\)
b) \(\sqrt{2,5\cdot14,4}=\sqrt{25\cdot144\cdot\frac{1}{100}}=\sqrt{25}\cdot\sqrt{144}\cdot\sqrt{\frac{1}{100}}=5\cdot12\cdot\frac{1}{10}=6\)
1
a,\(\sqrt{\dfrac{36}{121}}=\sqrt{\dfrac{6^2}{11^2}}=\dfrac{6}{11}\)
\(\sqrt{\dfrac{9}{16}:\dfrac{25}{36}}=\sqrt{\dfrac{81}{100}}=\sqrt{\dfrac{9^2}{10^2}}=\dfrac{9}{10}\)
2)
\(\sqrt{12,1.360}=\sqrt{12,1}.\sqrt{36}.\sqrt{10}\)
\(=\sqrt{12,1.36.10}\)
= \(\sqrt{121.36}\)
\(=\sqrt{4356}\)
\(=66\)
3)
\(\sqrt{5a}.\sqrt{45a}-3a\)
\(=\sqrt{5.45a^2}-3a\)
\(=\sqrt{225a^2}-3a\)
\(=\sqrt{\left(15a\right)^2}-3a\)
\(=-15a-3a\) ( vì \(a\le0\))
\(=-18a\)
5)
\(\sqrt{0,36a^2}\)
\(=\sqrt{\left(0,6a\right)^2}\)
\(=-0,6a\) ( vì \(a< 0\) )
Để tối mình rảnh lên coi có làm tiếp được nữa hông thì mình làm ha.
Chúc bạn học tốt!
1)
\(\sqrt{3a^3}.\sqrt{12}\)
\(=\sqrt{3}.\sqrt{a^3}.\sqrt{12}\)
\(=\sqrt{3.12}.\sqrt{a^3}\)
\(=6\sqrt{a^3}\)
4)
\(\left(3-a\right)^2-\sqrt{0,2}.\sqrt{180a^2}\)
\(=9.6a.a^2-\sqrt{0,2}.\sqrt{18}.\sqrt{10}.\sqrt{a^2}\)
\(=54a^3-\sqrt{2}.\sqrt{18}.\sqrt{a^2}\)
\(=34a^3-\sqrt{2.18}.\sqrt{a^2}\)
\(=54a^3-6\sqrt{a^2}\)
\(=54a^3-6a^2\) ( vì a<0)
6)
\(\sqrt{a^4.\left(3-a^{ }\right)^2}\)
\(=\sqrt{\left(a^2\right)^2.\left(3-a\right)^2}\)
\(=\sqrt{\left(a^2\right)^2}.\sqrt{\left(3-a\right)^2}\)
\(=\left|a^2\right|\left|3-a\right|\) ( vì a>3 => a>3 nên 3-a<0)
Mà\(\left|3-a\right|=-\left(-3-a\right)=-3+a=a-3\)
\(=a^2\left(a-3\right)\)
\(=a^3-3a^2\)
Còn lại bạn làm tương tự nha, trể quá rùi :)))))
Bài 1:
a: \(=\sqrt{225}=15\)
b: \(=\sqrt{\dfrac{2}{5}\cdot\dfrac{32}{5}}=\sqrt{\dfrac{64}{25}}=\dfrac{8}{5}\)
c: \(=\sqrt{121\cdot36}=11\cdot6=66\)
d: \(=7\cdot1.2\cdot5=35\cdot1.2=42\)
g: \(=\sqrt{\dfrac{27}{10}\cdot\dfrac{3}{2}\cdot5}=\sqrt{\dfrac{81}{20}\cdot5}=\sqrt{\dfrac{81}{4}}=\dfrac{9}{2}\)
Bài 2:
a: \(=\dfrac{1}{3}\cdot0.8\cdot8=\dfrac{8}{3}\cdot\dfrac{4}{5}=\dfrac{32}{15}\)
b: \(=\sqrt{\dfrac{100}{9}}=\dfrac{10}{3}\)
c: \(=\sqrt{\dfrac{1}{144}\cdot\dfrac{100}{49}}=\dfrac{1}{12}\cdot\dfrac{10}{7}=\dfrac{5}{6\cdot7}=\dfrac{5}{42}\)
a) ĐS: 2.4.
b) ĐS: 28.
c) HD: Đổi 12,1.360 thành 121.36. ĐS: 66
d) ĐS: 18.
a) \(\sqrt{0,09.64}\)
\(=\sqrt{0,09}.\sqrt{64}\)
\(=0,3.8=2,4\)
b) \(\sqrt{2^4.\left(-7\right)^2}\)
\(=\sqrt{2^4}.\sqrt{\left(-7\right)^2}\)
\(=2^2.7=4.7=28\)
c) \(\sqrt{12,1.360}\)
\(=\sqrt{121.36}\)
\(=\sqrt{121}.\sqrt{36}\)
\(=11.6=66\)
d) \(\sqrt{2^2.3^4}\)
\(=\sqrt{2^2}.\sqrt{3^4}\)
\(=2.3^2=2.9=18\)