Question

Bài 17 (trang 14 SGK Toán 9 Tập 1)

Áp dụng quy tắc khai phương một tích, hãy tính:

a) $\sqrt{0,09.64}$ ;                               b) $\sqrt{2^4.(-7)^2}$ ;

c) $\sqrt{12,1.360}$ ;                             d) $\sqrt{2^2.3^4}$

Answer 1

a, \(\sqrt{0.09\cdot64=\sqrt{0.09}\cdot\sqrt{64}=0.3\cdot8=2.4}\)

b, \(\sqrt{2^4\cdot\left(-7\right)^2}=\sqrt{16\cdot49}=\sqrt{16}\cdot\sqrt{49}=4\cdot7=28\)

c, \(\sqrt{121\cdot360}=\sqrt{121\cdot36}=\sqrt{121}\cdot\sqrt{36}=11\cdot6=66\)

d, \(\sqrt{2^2\cdot3^4}=\sqrt{2^2}\cdot\sqrt{3^4}=2\cdot3^2=18\)

Answer 2

a)\(\sqrt{0,09}.\sqrt{64}\)=0,3.8=2,4

b)\(\sqrt{2^4}.\sqrt{\left(-7\right)^2}\)=4.7=28

c)\(\sqrt{121.36}\)=\(\sqrt{121}.\sqrt{36}\)=11.6=66

d)\(\sqrt{2^2}.\sqrt{3^4}\)=2.9=18

Answer 3

a) $\sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}=0,3.8=2,4$.

b) $\sqrt{2^4.(-7{)}^2}=\sqrt{2^4}.\sqrt{(-7{)}^2}=2^2.|-7|=4.7=28$.

c) $\sqrt{12,1.360}=\sqrt{121.36}=\sqrt{{11}^2{.6}^2}=\sqrt{{11}^2}.\sqrt{6^2}=11.6=66$.

d) $\sqrt{2^2{.3}^4}=\sqrt{2^2}.\sqrt{3^4}={2.3}^2=18$

Answer 4

a) 2,4

b) 28

c) 66

d) 18

Answer 5

a) Ta có:

$\sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}$

                   $=\sqrt{(0,3{)}^2}.\sqrt{8^2}$

                   $=|0,3|.|8|$

                   $=0,3.8$

                   $=2,4$.

b) Ta có:

$\sqrt{2^4.(-7{)}^2}=\sqrt{2^4}.\sqrt{(-7{)}^2}$

                     $=\sqrt{(2^2{)}^2}.\sqrt{(-7{)}^2}$

                     $=\sqrt{4^2}.\left|-7\right|$

                     $=|4|.|-7|$

                     $=4.7$

                     $=28$.

c) Ta có:

$\sqrt{12,1.360}=\sqrt{12,1.\left(10.36\right)}$

                    $=\sqrt{(12,1.10).36}$

                    $=\sqrt{121.36}$

                    $=\sqrt{121}.\sqrt{36}$

                    $=\sqrt{{11}^2}.\sqrt{6^2}$

                    $=|11|.|6|$

                    $=11.6$

                    $=66$.

d) Ta có:

$\sqrt{2^2{.3}^4}=\sqrt{2^2}.\sqrt{3^4}$

              $=\sqrt{2^2}.\sqrt{(3^2{)}^2}$

              $=\sqrt{2^2}.\sqrt{9^2}$

              $=|2|.|9|$

              $=2.9$

              $=18$.

Xem thêm tại: https://loigiaihay.com/bai-17-trang-14-sgk-toan-9-tap-1-c44a3065.html#ixzz6ujMhFtvQ

Answer 6

Answer 7

a) $\sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}=0,3.8=2,4$.

b) $\sqrt{2^4.(-7{)}^2}=\sqrt{2^4}.\sqrt{(-7{)}^2}=2^2.|-7|=4.7=28$.

c) $\sqrt{12,1.360}=\sqrt{121.36}=\sqrt{{11}^2{.6}^2}=\sqrt{{11}^2}.\sqrt{6^2}=11.6=66$.

d) $\sqrt{2^2{.3}^4}=\sqrt{2^2}.\sqrt{3^4}={2.3}^2=18$.

Answer 8

a)0.24

b)28

c)66

d)18

 

Answer 9

a) \(\sqrt{0,09.64}=2.4\)

b) \(\sqrt{2^4.\left(-7\right)^2}=28\)

c) \(\sqrt{12,1.360}=66\)

d) \(\sqrt{2^2.3^4}=18\)

Answer 10

a)\(\sqrt{0,09\cdot64}=\sqrt{0,09}\cdot\sqrt{64}=0,3\cdot8=2,4\)

b)\(\sqrt{2^4\cdot\left(-7\right)^2}=\sqrt{2^4}\cdot\sqrt{7^2}=2^2\cdot7=4\cdot7=28\)

 

Answer 11

a) \sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}=0,3.8=2,40,09.64​=0,09​.64​=0,3.8=2,4.

b) \sqrt{2^4.(-7)^2}=\sqrt{2^4}.\sqrt{(-7)^2}=2^2.|-7|=4.7=2824.(−7)2​=24​.(−7)2​=22.∣−7∣=4.7=28.

c) \sqrt{12,1.360}=\sqrt{121.36}=\sqrt{11^2.6^2}=\sqrt{11^2}.\sqrt{6^2}=11.6=6612,1.360​=121.36​=112.62​=112​.62​=11.6=66.

d) \sqrt{2^2.3^4}=\sqrt{2^2}.\sqrt{3^4}=2.3^2=1822.34​=22​.34​=2.32=18.

Answer 12

Answer 13

a) \(\sqrt{0,09.64}=0,3.8=2,4\)

b) \(\sqrt{2^4.\left(-7\right)^2}=2^2.7=28\)

c) \(\sqrt{12,1.360}=\sqrt{121.36}=11.6=66\)

d) \(\sqrt{2^2.3^4}=2.3^2=18\)

\sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}=0,3.8=2,4

 

\sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}=0,3.8=2,4

 

Answer 14

Answer 15

a) \(\sqrt{0,09.64}=0,3.8=2,4\)

b) \(\sqrt{2^4.\left(-7\right)^2}=2^2.7=28\)

c) \(\sqrt{12,1.360}=\sqrt{121.36}=11.6=66\)

d) \(\sqrt{2^2.3^4}=2.3^2=18\)

 

Answer 16

a) \sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}=0,3.8=2,40,09.64​=0,09​.64​=0,3.8=2,4.

b) \sqrt{2^4.(-7)^2}=\sqrt{2^4}.\sqrt{(-7)^2}=2^2.|-7|=4.7=2824.(−7)2​=24​.(−7)2​=22.∣−7∣=4.7=28.

c) \sqrt{12,1.360}=\sqrt{121.36}=\sqrt{11^2.6^2}=\sqrt{11^2}.\sqrt{6^2}=11.6=6612,1.360​=121.36​=112.62​=112​.62​=11.6=66.

d) \sqrt{2^2.3^4}=\sqrt{2^2}.\sqrt{3^4}=2.3^2=1822.34​=22​.34​=2.32=18.

Answer 17

a) \(\sqrt{0,09.64}\)=\(\sqrt{0.09}\).\(\sqrt{64}\)=\(\sqrt{0,09}\).\(\sqrt{9}\).\(\sqrt{7}\)=6,3

b) \(\sqrt{2^4.\left(-7\right)^2}\)=\(2^2\).(-7)=4.(-7)=-28

c)\(\sqrt{12,1.360}\)=\(\sqrt{121.36}\)=11.6=66

d)\(\sqrt{2^2.3^4}\)=2.\(3^2\)=18

Answer 18

Answer 19

a)\(\sqrt{0,09.64}\)=0,3.8=2,4

b)\(\sqrt{2^4.\left(-7\right)^2}\)=\(2^2\).7=28

c)\(\sqrt{12,1.360}\)=\(\sqrt{121.36}\)=11.6=66

d)\(\sqrt{2^2.3^4}\)=2.\(3^2\)=18

Answer 20

a) \(\sqrt{0,09\cdot64}\)=\(\sqrt{0.09}\cdot\sqrt{64}\)=\(0.3\cdot8=2.4\)

b)\(\sqrt{2^4\cdot\left(-7\right)^2}=\sqrt{2^4}\cdot\sqrt{\left(-7\right)^2}=\)\(\sqrt{\left(2^2\right)^2}\cdot\overline{-7}\)\(=2^2\cdot7=4\cdot7=28\)

c) \(\sqrt{12.1\cdot360}=\sqrt{121\cdot36}=\sqrt{121}\cdot\sqrt{36}=11\cdot6=66\)

d)\(\sqrt{2^2\cdot3^4}=\sqrt{2^2}\cdot\sqrt{\left(3^2\right)^2}=\overline{2}\cdot3^2=2\cdot9=18\)

Answer 21

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) \(\sqrt{2^2.3^4}=\sqrt{2^2}.\sqrt{3^4}=2.3^2=18\)

Answer 22

a,\(\sqrt{0,09}\).\(\sqrt{64}\)=0,03.8=2,4

b,\(\sqrt{2^4}\).\(\sqrt{\left(-7\right)^2}\)=\(2^2\)./-7/=4.7=28

c,\(\sqrt{121.36}\)=\(\sqrt{121}\).\(\sqrt{36}\)=\(\sqrt{11^2}\).\(\sqrt{6^2}\)=11.6=66

d,\(\sqrt{2^2}\).\(\sqrt{3^4}\)=2.\(3^2\)=2.9=18

Answer 23

Answer 24

a) 2,4

b) 28

c) 66

d) 18 căn 2

Answer 25

Answer 26

Answer 27

Answer 28

Answer 29

Answer 30

a) $\sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}=0,3.8=2,4$.

b) $\sqrt{2^4.(-7{)}^2}=\sqrt{2^4}.\sqrt{(-7{)}^2}=2^2.|-7|=4.7=28$.

c) $\sqrt{12,1.360}=\sqrt{121.36}=\sqrt{{11}^2{.6}^2}=\sqrt{{11}^2}.\sqrt{6^2}=11.6=66$.

d) $\sqrt{2^2{.3}^4}=\sqrt{2^2}.\sqrt{3^4}={2.3}^2=18$.