bằng 49/24

đáp án là 49/24. Hok tốt

đề bài là tìm x hả bn

Đi 2, 3 thôi là đc.

Bài 3:

Bạn tham khảo

Nguồn : h.o.c24.vn

17.fast food

18.and

19.can

20.famous

21.same

hoc tot

Today fast food is very popular throughout the world. In the (17) fastfood restaurant you can get different kinds of food cheaply (18) and quickly. You can even take it home. For example, you (19) can get hot dogs or beefburgers in paper bags and boxes. Max Duffs is the name of a (20) famous fast food restaurant. Do you know that beefburgers in Mac Duffs in London tastes the (21) same as ones in Mac Duffs in Tokyo?

a, x : 1/3 = ( 1/3 ) ³

x=(1/3)^4

HT

Trả lời:

a, \(x\div\frac{1}{3}=\left(\frac{1}{3}\right)^3\)

\(\Leftrightarrow x=\left(\frac{1}{3}\right)^3\times\left(\frac{1}{3}\right)\)

\(\Leftrightarrow x=\left(\frac{1}{3}\right)^4\)

\(\Leftrightarrow x=\frac{1}{81}\)

b, \(x\div\left(\frac{1}{2}\right)^2=\frac{1}{16}\)

\(\Leftrightarrow x\div\left(\frac{1}{2}\right)^2=\left(\frac{1}{2}\right)^4\)

\(\Leftrightarrow x=\left(\frac{1}{2}\right)^4\times\left(\frac{1}{2}\right)^2\)

\(\Leftrightarrow x=\left(\frac{1}{2}\right)^6\)

\(\Leftrightarrow x=\frac{1}{64}\)

1) Tính :

a) \(\left(0,5\right)^3=0,125=\frac{1}{8}\)

b) \(\left(-\frac{1}{4}\right)^0=1\)

c) ...........

d) \(2^3+3.\left(\frac{1}{2}\right)^0-8=3\)

Trả lời:

a, \(\left(0,5\right)^3=0,125\)

b, \(\left(-\frac{1}{4}\right)^0=1\)

c, \(\left(\frac{3}{5}\right)^{15}:\left(\frac{9}{25}\right)^{15}=\frac{3^{15}}{5^{15}}:\frac{9^{15}}{25^{15}}=\frac{3^{15}}{5^{15}}.\frac{25^{15}}{9^{15}}=\frac{3^{15}}{5^{15}}.\frac{\left(5^2\right)^{15}}{\left(3^2\right)^{15}}=\frac{3^{15}}{5^{15}}.\frac{5^{30}}{3^{30}}=\frac{5^{15}}{3^{15}}\)

d, \(2^3+3.\left(\frac{1}{2}\right)^0-8=8+3.1-8=3\)

1) Viết các số sau dưới dạng lũy thừa

a) \(625=5^4\)

b) \(\frac{4}{9}=\left(\frac{2}{3}\right)^2\)

c) \(0,81=0,9^2\)

d) \(\frac{9}{64}=\left(\frac{3}{8}\right)^2\)

\(625=5^4\)

\(\frac{4}{9}=\left(\frac{2}{3}\right)^2\)

\(0,81=\left(0,9\right)^2\)

\(\frac{9}{64}=\left(\frac{3}{8}\right)^2\)

8) Ta có  \(2.16\ge2^n>4\Rightarrow2^5\ge2^n>2^2\)

=> \(5\ge n>2\)

\(\Rightarrow n\in\left\{3;4;5\right\}\)

b) Ta có \(9.27\le3^n\le243\)

\(\Rightarrow3^5\le3^n\le3^5\)

=> n = 5

9) 81ⁿ : 3ⁿ = 27

=> (81 : 3)ⁿ = 27

=> 27ⁿ = 27

=> n = 1

b) 25 : 5ⁿ = 5

=> 5ⁿ = 5

=> n = 1

c) \(\frac{81}{\left(-3\right)^n}=-27\)

=> (-3)ⁿ = (-3) 

=> n = 1

d) \(\frac{1}{2}.2^n+4.2^n=9.2^5\)

=> \(\frac{9}{2}.2^n=9.2^5\)

=> 2ⁿ = 2⁶

=> n = 6

Trả lời :

7) \(\left(-1\frac{1}{4}x^2y\right)^2\left(-\frac{5}{6}xy\right)^0\left(-2\frac{1}{2}xy\right)^5\)

Đáp án là : \(-\frac{78125x^9y^7}{512}\)

8) \(\left(\frac{-8}{3}x^2z\right)^3\left(\frac{2}{3}xy^2z^2\right)^3\left(\frac{4}{5}x^3y\right)\)

Đáp án là : .....

Câu 8 :

Tham khảo!

# R

Khi x = 9 

=> x + 1 = 10

Khi đó P(9) = x⁵⁰ - (x + 1)x⁴⁹ + (x + 1)x⁴⁸ - (x + 1)x⁴⁷ + ... + (x + 1)x - 1

= x⁵⁰ - x⁵⁰ - x⁴⁹ + x⁴⁹ + x⁴⁸ - x⁴⁸ - x⁴⁷ + ... + x² + x - 1

= x - 1 

= 9 - 1 = 8 

=8

tốt

hok

nha