Quy đồng hoặc tìm phần bù       

1: 243^5=(3^5)^5=3^25

3*27^8=3*(3^3)^8=3^25

=>243^5=3*27^8

6: 125^5=(5^3)^5=5^15

25^7=(5^2)^7=5^14

=>125^5>25^7(15>14)

5: 78^12-78^11=78^11(78-1)=78^11*77

78^11-78^10=78^10*77

mà 11>10

nên 78^12-78^11>78^11-78^10

Ta có: A = \(\frac{-2}{11}+\frac{6}{7}+\frac{1}{2}+\frac{-9}{11}+\frac{1}{7}\)
A = \(\left(\frac{-2}{11}+\frac{-9}{11}\right)+\left(\frac{6}{7}+\frac{1}{7}\right)+\frac{1}{2}\)

A = \(-1+1+\frac{1}{2}\)

A = \(\frac{1}{2}\)

B = \(\left(\frac{9}{16}+\frac{8}{27}\right)+\left(1+\frac{7}{16}+\frac{-19}{27}\right)\)

B = \(\frac{9}{16}+\frac{8}{27}+1+\frac{7}{16}-\frac{19}{27}\)

B = \(\left(\frac{9}{16}+\frac{7}{16}\right)+1+\left(\frac{8}{27}-\frac{19}{27}\right)\)

B = \(1+1-\frac{11}{27}\)

B = \(\frac{43}{27}\)

Mà 1/2 < 43/27 (Vì 1/2 < 1; 43/27 > 1)

=> A < B

                       Giải

\(A=\frac{-2}{11}+\frac{6}{7}+\frac{1}{2}+\frac{-9}{11}+\frac{1}{7}\)

\(\Leftrightarrow A=\left(\frac{-2}{11}+\frac{-9}{11}\right)+\left(\frac{6}{7}+\frac{1}{7}\right)+\frac{1}{2}\)

\(\Leftrightarrow A=\frac{-11}{11}+\frac{7}{7}+\frac{1}{2}\)

\(\Leftrightarrow A=-1+1+\frac{1}{2}\)

\(\Leftrightarrow A=\frac{1}{2}< 1\left(1\right)\)

\(B=\left(\frac{9}{16}+\frac{8}{27}\right)+\left(1+\frac{7}{16}+\frac{-19}{27}\right)\)

\(\Leftrightarrow B=\left(\frac{9}{16}+\frac{7}{16}\right)+\left(\frac{8}{27}+\frac{-19}{27}\right)+1\)

\(\Leftrightarrow B=\frac{16}{16}+\frac{-11}{27}+1\)

\(\Leftrightarrow B=1+\frac{-11}{27}+1\)

\(\Leftrightarrow B=2+\frac{-11}{27}\)

\(\Leftrightarrow B=\frac{43}{27}\)\(>1\left(2\right)\)

Từ (1) và (2) suy ra A < B

11^2<11^5

4^10>8^6

27^3<9^5

1: 243^5=(3^5)^5=3^25

3*27^8=3*3^24=3^25=243^5

3: 3^300=27^100

2^200=4^100

mà 27>4

nên 3^300>2^200

4: 15^2=3^2*5^2

81^3*125^3=3^12*5^9

=>15^2<81^3*125^3

6: 125^5=5^15

25^7=5^14

mà 15>14

nên 125^5>25^7

ta có \(-\frac{27}{463}< 0,\frac{1}{3}>0\)

\(\Leftrightarrow-\frac{27}{463}< 0< \frac{1}{3}\)

\(\Leftrightarrow-\frac{27}{463}< \frac{1}{3}\)

1/3 lớn hơn

giải chi tiết hộ mik cái nha mn

\(A=\left(\frac{20}{5}+\frac{27}{9}\right)\times\frac{21}{10}=\left(4+3\right)\times\frac{21}{10}=7\times\frac{21}{10}=\frac{147}{10}\)

\(B=\left(\frac{13}{6}-\frac{3}{8}\right)\times\frac{11}{22}\)

\(B=\left(\frac{52}{24}-\frac{9}{24}\right)\times\frac{11}{22}\)

\(B=\frac{43}{24}\times\frac{1}{2}=\frac{43}{48}\)

Dễ thấy \(A=\frac{147}{10}>1\)

Mà \(B=\frac{43}{48}< 1\)

=> tự so sánh

a: 3/5>-19/5

b: 8/7<8/3

c: 3/4=15/20

2/5=8/20

mà 15>8

nên 3/4>2/5

d: -3/5=-18/30

-4/6=-20/30

mà -18>-20

nên -3/5>-4/6

a: 3/5>-19/5

b: 8/7<8/3

c: 3/4=15/20

2/5=8/20

mà 15>8

nên 3/4>2/5

d: -3/5=-18/30

-4/6=-20/30

mà -18>-20

nên -3/5>-4/6