Question

[👁💧👄💧👁]

So sánh các phân số:

a) \(\dfrac{-47}{53}\) và \(\dfrac{-4747}{5353}\)

b) \(\dfrac{-19}{21}\) và \(\dfrac{1}{50}\)

c) \(\dfrac{-31}{128}\) và \(\dfrac{55}{-212}\)

d) \(\dfrac{23456}{-23457}\) và \(\dfrac{-4321}{4320}\)

e) \(\dfrac{19^{16}+1}{19^{17}+1}\) và \(\dfrac{19^{15}+1}{19^{16}+1}\)

Akai Haruma Phùng Tuệ Minh Nguyễn Việt Lâm Nguyễn Trương Nguyen DƯƠNG PHAN KHÁNH DƯƠNG Truong Viet Truong Khôi Bùi Ánh Lê saint suppapong udomkaewkanjana

Answer 1

[Ánh Lê]

a) \(-\dfrac{47}{53}=\dfrac{-47\cdot101}{53\cdot101}=\dfrac{-4747}{5353}\)

b)\(\dfrac{-19}{21}< 0\)

\(\dfrac{1}{50}>0\)

\(\Rightarrow-\dfrac{19}{21}< \dfrac{1}{50}\)

c)\(\dfrac{-31\cdot\left(-212\right)}{128\cdot\left(-212\right)}=\dfrac{-6572}{212\cdot128}\)

\(\dfrac{55\cdot128}{128\cdot\left(-212\right)}=\dfrac{-7040}{128\cdot212}\)

\(\Rightarrow\dfrac{-31}{128}>\dfrac{55}{-212}\)

d)

\(\dfrac{23456}{-23457}>-1\)

\(\dfrac{-4321}{4320}< -1\)

\(\Rightarrow\dfrac{23456}{-23457}>\dfrac{-4321}{4320}\)

e)

Học năm lớp 6 , giờ quên rồi :)))

Answer 2

[Khôi Bùi]

e ) \(A=\dfrac{19^{16}+1}{19^{17}+1};B=\dfrac{19^{15}+1}{19^{16}+1}\)

\(\Rightarrow19A=\dfrac{19^{17}+19}{19^{17}+1}=1+\dfrac{18}{19^{17}+1}\)

\(19B=\dfrac{19^{16}+19}{19^{16}+1}=1+\dfrac{18}{19^{16}+1}\)

Do \(\dfrac{18}{19^{16}+1}>\dfrac{18}{19^{17}+1}\)

\(\Rightarrow1+\dfrac{18}{19^{16}+1}>1+\dfrac{18}{19^{17}+1}\)

\(\Rightarrow19B>19A\)

\(\Rightarrow B>A\)