Rút gọn: \(\frac{56}{49}=\frac{8}{7}\)

\(\frac{y}{7}=\frac{8}{7}\Rightarrow y=8\)

Rút gọn: \(\frac{15}{27}=\frac{5}{9}\)

\(\frac{5}{9}=\frac{5}{y}\Rightarrow y=9\)

a) y/7=56/49=> 7.56=y.49

=> y=7.56:49

=>y=8 vậy y=8

b)15/49=5/y

=> 15y=27.5 

=> y=27.5:15

=>y=9 vậy y=9

@Thutrang và mình làm 2 cách khác nhau

Mà bài này không cần nhân chéo chia ngang đâu @trang

\(a,\Rightarrow7y=56\Leftrightarrow y=8\)

b, \(\Rightarrow3y=27\Leftrightarrow y=9\)

a) y.49 = 56.7

y.49=392

y=392:49

y=8

b)15.y=27.5

15.y= 135

y=135:15

y=9

(tick nhé)

a: x=27

a: x=27

a, 3/5 < 11/3

b, 5/4 > 4/5

c, 13/27 > 4/9

d, 7/8 = 49/56

\(\dfrac{120}{150}+\dfrac{15}{27}=\dfrac{4}{5}+\dfrac{5}{9}=\dfrac{36}{45}+\dfrac{25}{45}=\dfrac{61}{45}\)

b

\(\dfrac{42}{49}+\dfrac{56}{84}=\dfrac{6}{7}+\dfrac{14}{21}=\dfrac{18}{21}+\dfrac{14}{21}=\dfrac{32}{21}\)

150/120 + 15/27
= 5/3 + 5/9
= 20/9

42/49 + 56/84
= 6/7 + 2/3
= 32/21

\(\dfrac{150}{120}+\dfrac{15}{27}=\)

 \(\dfrac{4}{5}+\dfrac{5}{9}=\dfrac{36}{45}+\dfrac{25}{45}=\dfrac{61}{45}\)

b.\(\dfrac{42}{49}+\dfrac{56}{84}\)

= \(\dfrac{18}{21}+\dfrac{14}{21}\)

= \(\dfrac{32}{21}\)

a, (-72).(15 - 49) + 15.(-56 + 72)

= -72 . 15 + 72.49  - 15.56 + 15.72

= (-72.15 + 15.72) + (72.49  - 15.56)

= 3528 - 84

= 2688

1b, 1532 + (-186) + (-1432) + (-14) + 123

= (1532 - 1432) - (186 + 14) + 123

= 100 - 200 + 123

= 223 - 200

= 23 

43.(53 - 81) + 53.(81 - 43)

= 43.53 - 81.43 + 53.81 - 53.43

= (43.53 - 53.43) + (81.53 - 81.43)

= 0 + 81.(53-43)

= 81.10

= 810