Question

Bài 11 (trang 11 SGK Toán 9 Tập 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) $\sqrt{3^2+4^2}$.

Answer 1

a) \(\sqrt{16}\).\(\sqrt{25}\)+\(\sqrt{196}\):\(\sqrt{49}\)

=4.5+14/7

=20+2

=22

Answer 2

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

Answer 3

a, 4.5+ 14:7= 20+2= 22

b, 36: √2.9.18 - 13 = 36:18 -13 =-11

c, √9 = 3

d, √9+16 = √25 = 5

Answer 4

a) \(\sqrt{16}\times\sqrt{25}+\sqrt{196}\div\sqrt{49}=4\times5+14\div7=20+2=22\)

b) \(36\div\sqrt{2\times3^2\times18}-\sqrt{169}=36\div18-13=2-13=-11\)

c) \(\sqrt{\sqrt{81}}=3\)

d) \(\sqrt{3^2+4^2}=5\)

Answer 5

Answer 6

a.22

b.-11

c.3

d.5

Answer 7

Answer 8

Answer 9

Answer 10

a. \(\sqrt{16}\) . \(\sqrt{25}\) + \(\sqrt{196}\) : \(\sqrt{49}\)
= \(\sqrt{4^2}\) . \(\sqrt{5^2}\) + \(\sqrt{14^2}\) : \(\sqrt{7^2}\)
= 4.5 + 14:7 = 20+2=22
b. \(\sqrt{36}\) : \(\sqrt{2.3^2.18}\) - \(\sqrt{169}\)
= 36 : \(\sqrt{3^2.36}\) - \(\sqrt{13^2}\)
= 36 : 18 - 13 = 2-13 =  -11
c.\(\sqrt{\sqrt{81}}\) = \(\sqrt{\sqrt{9^2}}\) = \(\sqrt{9}\) = \(\sqrt{3^2}\) = 3
d. \(\sqrt{3^2+4^2}\) = \(\sqrt{25}\) = \(\sqrt{5^2}\) = 5

Answer 11

Answer 12

a) $\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}$

$=\sqrt{4^2}.\sqrt{5^2}+\sqrt{{14}^2}:\sqrt{7^2}$

$=4.5+14:7=20+2=22$

b) $\sqrt{36}:\sqrt{{2.3}^2.18}-\sqrt{169}$

$=36:\sqrt{3^2.36}-\sqrt{{13}^2}$

$=36:\sqrt{3^2{.6}^2}-13=36:\sqrt{{18}^2}-13$

$=36:18-13=2-13=-11$.

c) $\sqrt{\sqrt{81}}=\sqrt{\sqrt{9^2}}=\sqrt{9}=\sqrt{3^2}=3$

d) $\sqrt{3^2+4^2}=\sqrt{25}=\sqrt{5^2}=5$

Answer 13

Answer 14

a) = 4.5 + 14 : 7 = 20 + 2 = 22

b) 36 : 18 - 13 = 2 - 13 = - 11

c) \(\sqrt{9}\) = 3

d) \(\sqrt{9+16}\) = \(\sqrt{25}\) = 5

Answer 15

a) $\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}$

$=\sqrt{4^2}.\sqrt{5^2}+\sqrt{{14}^2}:\sqrt{7^2}$

$=4.5+14:7=20+2=22$.

b) $\sqrt{36}:\sqrt{{2.3}^2.18}-\sqrt{169}$

$=36:\sqrt{3^2.36}-\sqrt{{13}^2}$

$=36:\sqrt{3^2{.6}^2}-13=36:\sqrt{{18}^2}-13$

$=36:18-13=2-13=-11$.

c) $\sqrt{\sqrt{81}}=\sqrt{\sqrt{9^2}}=\sqrt{9}=\sqrt{3^2}=3$.

d) $\sqrt{3^2+4^2}=\sqrt{25}=\sqrt{5^2}=5$.

Answer 16

a) $\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}$

$=\sqrt{4^2}.\sqrt{5^2}+\sqrt{{14}^2}:\sqrt{7^2}$

$=4.5+14:7=20+2=22$.

b) $\sqrt{36}:\sqrt{{2.3}^2.18}-\sqrt{169}$

$=36:\sqrt{3^2.36}-\sqrt{{13}^2}$

$=36:\sqrt{3^2{.6}^2}-13=36:\sqrt{{18}^2}-13$

$=36:18-13=2-13=-11$.

c) $\sqrt{\sqrt{81}}=\sqrt{\sqrt{9^2}}=\sqrt{9}=\sqrt{3^2}=3$.

d) $\sqrt{3^2+4^2}=\sqrt{25}=\sqrt{5^2}=5$

 

Answer 17

Answer 18

Answer 19

Answer 20

a) \(\sqrt{4^2}.\sqrt{5^2}+\sqrt{14^2}:\sqrt{7^2}\) = \(|4|.|5|+|14|:|7|\) = 4.5+14:7 = 20+2 = 22

b) 36:\(\sqrt{2.9.2.9}-\sqrt{169}\) = 36:\(\sqrt{4}.\sqrt{9}.\sqrt{9}-\sqrt{169}\) = 2.3.3-13 = 18-3 = 15

c)\(\sqrt{\sqrt{9.9}}\) = \(\sqrt{\sqrt{9}.\sqrt{9}}\) = \(\sqrt{3.3}\) = \(\sqrt{9}\) = 3

d)\(\sqrt{9+16}=\sqrt{25}=5\)

Answer 21

a) Ta có: $\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}$

$=\sqrt{4^2}.\sqrt{5^2}+\sqrt{{14}^2}:\sqrt{7^2}$

$=\left|4\right|.\left|5\right|+\left|14\right|:\left|7\right|$

$=4.5+14:7$

$=20+2=22$. 

b) Ta có:

 $36:\sqrt{{2.3}^2.18}-\sqrt{169}$

$=36:\sqrt{\left({2.3}^2\right).18}-\sqrt{{13}^2}$

$=36:\sqrt{\left(2.9\right).18}-\left|13\right|$

$=36:\sqrt{18.18}-13$  

$=36:\sqrt{{18}^2}-13$

$=36:\left|18\right|-13$

$=36:18-13$ 

$=2-13=-11$.

c) Ta có: $\sqrt{81}=\sqrt{9^2}=\left|9\right|=9$.

 $\Rightarrow \sqrt{\sqrt{81}}$$=\sqrt{9}=\sqrt{3^2}=\left|3\right|=3$.

d) Ta có: $\sqrt{3^2+4^2}=\sqrt{16+9}=\sqrt{25}$$=\sqrt{5^2}=\left|5\right|=5$.

 

Answer 22

Answer 23

a) Ta có: $\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}$

$=\sqrt{4^2}.\sqrt{5^2}+\sqrt{{14}^2}:\sqrt{7^2}$

$=\left|4\right|.\left|5\right|+\left|14\right|:\left|7\right|$

$=4.5+14:7$

$=20+2=22$

b) Ta có:

 $36:\sqrt{{2.3}^2.18}-\sqrt{169}$

$=36:\sqrt{\left({2.3}^2\right).18}-\sqrt{{13}^2}$

$=36:\sqrt{\left(2.9\right).18}-\left|13\right|$

$=36:\sqrt{18.18}-13$  

$=36:\sqrt{{18}^2}-13$

$=36:\left|18\right|-13$

$=36:18-13$ 

$=2-13=-11$

c) Ta có: $\sqrt{81}=\sqrt{9^2}=\left|9\right|=9$

 $\Rightarrow \sqrt{\sqrt{81}}$$=\sqrt{9}=\sqrt{3^2}=\left|3\right|=3$

d) Ta có: $\sqrt{3^2+4^2}=\sqrt{16+9}=\sqrt{25}$$=\sqrt{5^2}=\left|5\right|=5$

 

Answer 24

Answer 25

Answer 26

Answer 27

a) \(\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}\) = \(\sqrt{4^2}.\sqrt{5^2}+\sqrt{14^2}:\sqrt{7^2}\) = \(\left|4\right|.\left|5\right|+\left|14\right|.\left|7\right|\) = 4.5 + 14.7 =20 + 2 = 22

b)

Answer 28

 \sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}16​.25​+196​:49​

=\sqrt{4^2}.\sqrt{5^2}+\sqrt{14^2}:\sqrt{7^2}=42​.52​+142​:72​

$=4.5+14:7=20+2=22$.

b) \sqrt{36}:\sqrt{2.3^2.18}-\sqrt{169}36​:2.32.18​−169​

=36:\sqrt{3^2.36}-\sqrt{13^2}=36:32.36​−132​

= 36:\sqrt{3^2.6^2}-13=36:\sqrt{18^2}-13=36:32.62​−13=36:182​−13

$=36:18-13=2-13=-11$.

c) \sqrt{\sqrt{81}}=\sqrt{\sqrt{9^2}}=\sqrt{9}=\sqrt{3^2}=381​​=92​​=9​=32​=3.

d) \sqrt{3^2+4^2}=\sqrt{25}=\sqrt{5^2}=532+42​=25​=52​=5.

Answer 29

a) \(\sqrt{16}.\sqrt{25}\) + \(\sqrt{169}:\sqrt{49}\)

= \(\sqrt{4^2}\).\(\sqrt{5^2}\) + \(\sqrt{14^2}:\sqrt{7^2}\)

= 4.5 + 14 : 7 

= 20 + 2 = 22

b) \(\sqrt{36}:\sqrt{2.3^2.18}-\sqrt{169}\)

= 36 : \(\sqrt{3^2.36}-\sqrt{13^2}\)

= 36 : \(\sqrt{3^2.6^2}-13\)

= 36 : \(\sqrt{18^2}-13\)

= 36 : 18 - 13 = 2 - 13 = -11

c) \(\sqrt{\sqrt{81}}=\sqrt{\sqrt{9^2}}=\sqrt{9}=\sqrt{3^2}=3\) 

d) \(\sqrt{3^2+4^2}=\sqrt{25}=\sqrt{5^2}=5\)

 

Answer 30

\(a,\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49}=4.5+14:7=20+2=22\)

b,\(36:\sqrt{2.3^2.18}-\sqrt{169}=36:\sqrt{324}-13=36:18-13=2-13=-11\)

c, \(\sqrt{\sqrt{81}}=3\)

d, \(\sqrt{3^2+4^2}=\sqrt{9+16}=\sqrt{25}=5\)