Bài 1: Tính
a) \(\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}\)
b) \(36:\sqrt{2.3^2.18}-\sqrt{169}\)
c) \(\sqrt{\sqrt{81}}\)
d) \(\sqrt{3^2+4^2}\)
Bài 2:
Cho tam giác ABC vuông tại A có b=10,\(\widehat{C}=30^o\)
Giải tam giác vuông ABC
K
Khách
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DM
31 tháng 3 2017
a) \(\sqrt{16}\cdot\sqrt{25}+\sqrt{196}:\sqrt{49}\)
\(=\sqrt{16\cdot25}+\sqrt{196:49}\)
\(=20+2=22\)
b) \(36:\sqrt{2\cdot3^2\cdot18}-\sqrt{169}\)
\(=36:\sqrt{324}-\sqrt{169}\)
\(=36:18-13=2-13=-11\)
c) \(\sqrt{\sqrt{81}}\)
\(=\sqrt{9}=3\)
d) \(\sqrt{3^2+4^2}\)
\(=\sqrt{9+16}=\sqrt{25}=5\)
7 tháng 6 2017
a) \(\sqrt{16}.\sqrt{25}+\sqrt{196}\div\sqrt{49}\)
\(=4.5+14:7\)
\(=20+2=22\)
b) \(36:\sqrt{2.3^2.18}-\sqrt{169}\)
\(=36:18-13=-11\)
c) \(\sqrt{\sqrt{81}}=\sqrt{9}=3\)
d) \(\sqrt{3^2+4^2}=\sqrt{25}=5\)
NM
14 tháng 4 2021
a) \(\sqrt{16}\).\(\sqrt{25}\)+\(\sqrt{196}\):\(\sqrt{49}\)
=4.5+14/7
=20+2
=22
PB
21 tháng 5 2021
a) \(\sqrt{16}\).\(\sqrt{25}\) + \(\sqrt{196}\) : \(\sqrt{49}\) = 4.5+14:9=22
b) 36:\(\sqrt{2.3^2.18}\) - \(\sqrt{169}\)= 36 : \(\)18 - 13 = -11
c) \(\sqrt{\sqrt{81}}\) = 3
d) \(\sqrt{3^2+4^2}\)= \(\sqrt{25}\)=5
25 tháng 10 2022
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: \(=\dfrac{2}{3}\cdot\dfrac{9}{4}-\dfrac{3}{4}\cdot\dfrac{8}{3}+\dfrac{7}{5}\cdot\dfrac{5}{14}=\dfrac{3}{2}-2+\dfrac{1}{2}=2-2=0\)
21 tháng 12 2017
1. Rút gọn biểu thức:
a) \(\sqrt{\dfrac{81}{25}.\dfrac{49}{16}.\dfrac{9}{196}}=\sqrt{\dfrac{81}{25}}.\sqrt{\dfrac{49}{16}}.\sqrt{\dfrac{9}{4.49}}=\dfrac{9}{5}.\dfrac{7}{4}.\dfrac{3}{2.7}=\dfrac{9.3}{5.4.2}=\dfrac{27}{40}\)
b) \(\sqrt{72}-5\sqrt{2}-\sqrt{49.3}+\sqrt{48}+\sqrt{12}=\)
\(=\sqrt{9.4.2}-5\sqrt{2}-\sqrt{49.3}+\sqrt{16.3}+\sqrt{4.3}\)
\(=3.2\sqrt{2}-5\sqrt{2}-7\sqrt{3}+4\sqrt{3}+2\sqrt{3}\)
\(=6\sqrt{2}-5\sqrt{2}-7\sqrt{3}+4\sqrt{3}+2\sqrt{3}\)
\(=\sqrt{2}-\sqrt{3}\)
c) \(\sqrt{\left(2-\sqrt{3}\right)^2}+\sqrt{\left(2+\sqrt{3}\right)^2}=\) \(=\left|2-\sqrt{3}\right|+\left|2+\sqrt{3}\right|=2-\sqrt{3}+2+\sqrt{3}=4\)
d) \(\sqrt{5}+\sqrt{20}-\sqrt{45}+3\sqrt{18}+\sqrt{72}=\)
\(=\sqrt{5}+\sqrt{4.5}-\sqrt{9.5}+3\sqrt{9.2}+\sqrt{9.4.2}\)
\(=\sqrt{5}+2\sqrt{5}-3\sqrt{5}+3.3\sqrt{2}+3.2\sqrt{2}\)
\(=\sqrt{5}+2\sqrt{5}-3\sqrt{5}+9\sqrt{2}+6\sqrt{2}\)
\(=15\sqrt{2}\)
KH
21 tháng 9 2017
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~
5 tháng 10 2023
`#3107.101107`
a)
`2/5 \sqrt{25} - 1/2 \sqrt{4}`
`= 2/5 * \sqrt{5^2} - 1/2 * \sqrt{2^2}`
`= 2/5*5 - 1/2*2`
`= 2 - 1`
`= 1`
b)
`0,5*\sqrt{0,09} + 5*\sqrt{0,81}`
`= 0,5*\sqrt{(0,3)^2} + 5*\sqrt{(0,9)^2}`
`= 0,5*0,3 + 5*0,9`
`= 0,15 + 4,5`
`= 4,65`
c)
`2/5\sqrt{25/36} - 5/2\sqrt{4/25}`
`= 2/5*\sqrt{(5^2)/(6^2)} - 5/2*\sqrt{(2^2)/(5^2)}`
`= 2/5*5/6 - 5/2*2/5`
`= 1/3 - 1`
`= -2/3`
d)
`-2 \sqrt{(-36)/(-16)} + 5 \sqrt{(-81)/(-25)}`
`= -2*\sqrt{36/16} + 5*\sqrt{81/25}`
`= -2*\sqrt{(6^2)/(4^2)} + 5*\sqrt{(9^2)/(5^2)}`
`= -2*6/4 + 5*9/5`
`= -3 + 9`
`= 6`
Bài làm:
Bài 1:
a)\(\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}\)
= 4.5 + 14 : 7
= 20 + 2
= 22
b)\(36:\sqrt{2.3^2.18}-\sqrt{169}\)
= 36 : 18 - 14
= 2 - 14
= - 12
c)\(\sqrt{\sqrt{81}}\) = \(\sqrt{9}\) = 3
d)\(\sqrt{3^2+4^2}\)
= \(\sqrt{9+16}\)
= \(\sqrt{25}\)
= 5
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