a)\(\frac{1}{8}>0;\frac{-3}{7}< 0\Rightarrow\frac{1}{8}>0>\frac{-3}{7}\Rightarrow\frac{1}{8}>\frac{-3}{7}\)

b)\(\frac{-3}{7}< 0;2\frac{1}{2}>0\Rightarrow\frac{-3}{7}< 0< 2\frac{1}{2}\Rightarrow\frac{-3}{7}< 2\frac{1}{2}\)

c)\(-3,9< 0;0,1>0\Rightarrow-3,9< 0< 0,1\Rightarrow-3,9< 0,1\)

d)\(-2,3< 0;3,2>0\Rightarrow-2,3< 0< 3,2\Rightarrow-2,3< 3,2\)

1/8>-3/7

-3/7<2 1/2

-3.9 <0.1

-2.3<3.2

ôi trời :-3.9<0 và 0.1>0 =>-3.9>0.1

-2.3<0 và 3.2>0 =>-2.3<3.2

a) Ta có:

-3 . 9 = -27

0 . 1 = 0

Vì -27 < 0 nên -3 . 9 < 0 . 1

b) Ta có:
-2 . 3 = -6

3 . 2 = 6

Vì 6 < - 6 nên -2 . 3 < 3 . 2 

3² > 3.2

nhớ cho tick!

3^2=9                                                                                                      3.2=6                                                                                                         3^2 > 3.2

Ta có: 3 .(2+5) = 3.7 = 21

3.2+ 3.5 = 6 + 15 = 21

Vậy 3.(2+5) = 3.2 +3.5

3.(2 + 5) = 3.7 = 21

3.2 + 3.5 = 6 + 15 = 21

⇒ 3.(2 + 5) = 3.2 + 3.5

Ta có: \({\left( {{{15}^3}} \right)^2}\) = 15³ . 15³ = 15³⁺³ = 15⁶

\({15^{3.2}}\) = 15⁶

Vậy \({\left( {{{15}^3}} \right)^2}\) = \({15^{3.2}}\)

2^m+2 > 3.2^m

BCNN=36

\(\dfrac{5}{36}=\dfrac{5}{36}>0>-\dfrac{7}{12}\)

oki  :

TL:

BCNN=36

\(81\cdot7=3^4\cdot7\)

\(2\cdot3^5=2\cdot3\cdot3^4=6\cdot3^4\)

mà \(7>6\Rightarrow3^4\cdot7>3^4\cdot6\)

\(\Rightarrow81.7>2\cdot3^5\)

\(\text{Ta có:}\)

\(81\cdot7=3^4\cdot7\)

\(2\cdot3^5=2\cdot3\cdot3^4=6\cdot3^4\)

\(\text{Vì}\) \(3^4\cdot7>6\cdot3^4\Rightarrow81\cdot7>2\cdot3^5\)

Ta có: 1/2.3 =1/2-1/3

Vì 1/2-1/3=1/2-1/3

Vậy 1/2.3 = 1/2-1/3