Câu 1:

MSC=60

7/10=7.6/10.6=42/60            5/-12=-5/12=-5.5/12.5=-25/60

Câu 2:

17/34=1/2;  -12/22=-6/11;  -25/35=-5/7;  125/75=5/3

Câu 3:

MSC=24

1/3=1.8/3.8=8/24     -3/8=-3.3/8.3=-9/24           17/24=17/24

_{Làm ơn giúp mình với !}

b, \(\dfrac{7}{13}\) và \(\dfrac{17}{23}\) 

\(\dfrac{7}{13}\) <  \(\dfrac{7+10}{13+10}\) = \(\dfrac{17}{23}\)

Vậy \(\dfrac{7}{13}\) < \(\dfrac{17}{23}\) 

\(\dfrac{12}{48}\) =  \(\dfrac{12:12}{48:12}\)  = \(\dfrac{1}{4}\) 

\(\dfrac{13}{47}\) > \(\dfrac{13}{52}\) = \(\dfrac{13:13}{52:13}\) = \(\dfrac{1}{4}\) 

Vậy  \(\dfrac{12}{48}\) < \(\dfrac{13}{47}\) 

a. Ta tính trước số bị chia: 1 + 4 + 7 + …… + 100

Dãy số gồm có:     (100 – 1) : 3 + 1 = 34 (số hạng)

Ta thấy: 1 + 100 = 4 + 97 = 101 = …..

Do đó số bị chia là: 101 x 34 : 2 = 1717

Ta có:   1717 : a = 17

a = 1717 : 17

a = 101

vậy a = 101.

b.

x - 1 2 × 5 3 = 7 4 - 1 2 x - 1 2 × 5 3 = 5 4 x - 1 2 = 5 4 : 5 3 x - 1 2 = 3 4 x = 3 4 + 1 2 x = 5 4

c.  2000 2001   v à   2001 2002

Ta có: 1 - 2000 2001 =  1 2001

1 - 2001 2002 = 1 2002

Vì  1 2001 >  1 2002 nên 2000 2001  <  2001 2002

a: \(\dfrac{5}{7}=\dfrac{5\cdot11}{7\cdot11}=\dfrac{55}{77}\)

\(\dfrac{9}{11}=\dfrac{9\cdot7}{11\cdot7}=\dfrac{63}{77}\)

b: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot9}{7\cdot9}=\dfrac{54}{63}\)

\(-\dfrac{12}{54}=\dfrac{-2}{9}=\dfrac{-2\cdot7}{9\cdot7}=-\dfrac{14}{63}\)

c: \(\dfrac{-11}{30}=\dfrac{-11\cdot4}{30\cdot4}=\dfrac{-44}{120}\)

\(\dfrac{-17}{-40}=\dfrac{17}{40}=\dfrac{17\cdot3}{40\cdot3}=\dfrac{51}{120}\)

d: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot3}{7\cdot3}=\dfrac{18}{21}\)

\(\dfrac{-12}{36}=\dfrac{-1}{3}=\dfrac{-1\cdot7}{3\cdot7}=\dfrac{-7}{21}\)

\(\frac{-11}{12}\)và\(\frac{17}{-18}\)

\(\Rightarrow\frac{-11}{12}\) và \(\frac{-17}{18}\)

Mẫu Số Chung là:108

\(\frac{-11}{12}=\frac{-11\cdot9}{12\cdot9}=\frac{-99}{108}\)

\(\frac{-17}{18}=\frac{-17\cdot6}{18\cdot6}=\frac{-102}{108}\)

ta có: \(\frac{17}{-18}\)=\(\frac{-17}{18}\)

12=2 mũ 2 x 3

18=2x 3 mũ 2

=>BCNN(12,18)=2 mũ 2 x 3 mũ 3 =36

Các thừa số chung:

36 :12=3

36:18=2

Quy đồng:

\(\frac{-11}{12}\)=\(\frac{-11x3}{12x3}\)=\(\frac{-33}{36}\)

\(\frac{-17}{18}\)=\(\frac{-17x2}{18x2}\)=\(\frac{-34}{36}\)

ta có: \(\frac{-11}{12}=\frac{17}{-18}\)

\(\Rightarrow\)\(\frac{-11}{12}=\frac{-12}{18}\)

msc là: \(36\)

quy đồng mẫu số

\(\frac{-11}{12}=\frac{-11\times3}{12\times3}=\frac{-33}{36}\)

\(\frac{-17}{18}=\frac{-17\times2}{18\times2}=\frac{-34}{36}\)

\(30/55; 77/55\)

\(14/12; 17/12\)

30/55 ; 77/55

14/12 ; 17/12

\(\dfrac{30}{55}\)và\(\dfrac{77}{55}\)

\(\dfrac{14}{12}\)và\(\dfrac{17}{12}\)

CHÚC HOK TỐT NHA B

help me

trả lời đúng tui k cho :3