Question

[Mai Ngọc Trâm]

1. Tính :

a. \(\dfrac{9^6.9^{10}}{3^{32}}\) ; b. \(\dfrac{25^8.25^{10}}{5^{34}}\) ; c. \(\dfrac{7^{56}}{49^9.49^{20}}\) ; d. \(\dfrac{4^2.4^3}{2^{10}}\) ; e. \(\dfrac{2^{17}.25^5}{10^8.8^3}\) ; f. \(\dfrac{3^{15}.25^4}{15^6.8^3}\)

2. Tính lũy thừa âm :

a. 3^-2 b. 2^-3

3. Tính :

a. \(\dfrac{\left(0,8\right)^{17}}{\left(0,4\right)^3}\) ; b. \(\dfrac{\left(0,8\right)^3}{\left(0,4\right)^4}\) ; c. \(\dfrac{\left(0,6\right)^5}{\left(0,2\right)^6}\)

Giải giùm mk mấy câu này nha!!!!

Answer 1

[Nguyễn Hải Dương]

cứ phan tích cho hết đi là đc 9^6. 9^10 = (3^2)^6...................

tự làm đi

Answer 2

[Thịnh Xuân Vũ]

1. Tính:

a. \(\dfrac{9^6.9^{10}}{3^{32}}=\dfrac{\left(3^2\right)^6.\left(3^2\right)^{10}}{3^{32}}=\dfrac{3^{12}.3^{20}}{3^{32}}=\dfrac{3^{32}}{3^{32}}=1\)

b. \(\dfrac{25^8.25^{10}}{5^{34}}=\dfrac{\left(5^2\right)^8.\left(5^2\right)^{10}}{5^{34}}=\dfrac{5^{16}.5^{20}}{5^{34}}=\dfrac{5^{36}}{5^{34}}=5^{36}:5^{34}=5^2=25\)

c. \(\dfrac{7^{56}}{49^9.49^{20}}=\dfrac{7^{56}}{\left(7^2\right)^9.\left(7^2\right)^{20}}=\dfrac{7^{56}}{7^{18}.7^{40}}=\dfrac{7^{56}}{7^{58}}=7^{56}:7^{58}=\dfrac{7^{56}}{7^{56}.7^2}=\dfrac{1}{7^2}=\dfrac{1}{49}\)

d. \(\dfrac{4^2.4^3}{2^{10}}=\dfrac{\left(2^2\right)^2.\left(2^2\right)^3}{2^{10}}=\dfrac{2^4.3^6}{2^{10}}=\dfrac{2^{10}}{2^{10}}=1\)

e. \(\dfrac{2^{17}.25^5}{10^8.8^3}=\dfrac{2^{17}.\left(5^2\right)^5}{\left(2.5\right)^8.\left(2^3\right)^3}=\dfrac{2^{17}.5^{10}}{2^8.5^8.2^9}=\dfrac{2^{17}.5^{10}}{2^{17}.5^8}=\dfrac{5^{10}}{5^8}=5^{10}:5^8=5^2=25\)

f. \(\dfrac{3^{15}.25^4}{15^6.27^3}=\dfrac{3^{15}.\left(5^2\right)^4}{\left(3.5\right)^6.\left(3^3\right)^3}=\dfrac{3^{15}.5^8}{5^6.3^6.3^9}=\dfrac{3^{15}.5^8}{5^6.3^6.3^9}=\dfrac{5^8}{5^6}=5^8:5^6=5^2=25\)

2. Tính lũy thừa âm:

a. 3^-2 = \(\dfrac{1}{3^2}\) = \(\dfrac{1}{9}\)

b. 2^-3 = \(\dfrac{1}{2^3}\) = \(\dfrac{1}{8}\)

3. Tính :

a. \(\dfrac{\left(0,8\right)^4}{\left(0,4\right)^3}=\dfrac{\left(0,8\right)^3.0,8}{\left(0,4\right)^3}=\left(\dfrac{0,8}{0,4}\right)^3.0,8=2^3.0,8=8.0,8=6,4\)

b. \(\dfrac{\left(0,8\right)^3}{\left(0,4\right)^4}=\dfrac{\left(0,8\right)^3}{\left(0,4\right)^3:0,4}=\left(\dfrac{0,8}{0,4}\right)^3.\dfrac{1}{0,4}=2^3.2,5=8.2,5=20\)

c. \(\dfrac{\left(0,6\right)^5}{\left(0,2\right)^6}=\dfrac{\left(0,6\right)^5}{\left(0,2\right)^5.\left(0,2\right)}=\left(\dfrac{\left(0,6\right)}{\left(0,2\right)}\right)^5.\dfrac{1}{0,2}=3^5.\dfrac{1}{0,2}=\dfrac{3^5}{0,2}=1215\)

P/s : Chế Mai Ngọc Trâm thử tham khảo thử đi!!!