( 1/10 + 2/9 + 3/8 + 4/7 + 5/6 + 1/6 + 3/7 + 5/8 + 7/9 + 9/10 ) * 48

= [ ( 1/10 + 9/10 ) + ( 2/9 + 7/9 ) + ( 3/8 + 5/8 ) + ( 4/7 + 3/7 ) + ( 5/6 + 1/6 ) ] * 48

=( 1 + 1 + 1 + 1 +  ) *48

=5 * 48

= 240

`a) 5 / 13 xx 4 / 15 xx 13 = [ 5 xx 4 xx 13 ] / [ 13 xx 5 xx 3 ] = 4 / 3`

`b) ( 3 / 7 + 5 / 2 ) xx 7 / 5 = 3 / 7 xx 7 / 5 + 5 / 2 xx 7 / 5 = 3 / 5 + 7 / 2 = 6 / 10 + 35 / 10 = 41 / 10`

`c) 1 / 5 xx 11 / 18 + 11 / 18 xx 3 / 5 = 11 / 18 xx ( 1 / 5 + 3 / 5 ) = 11 / 18 xx 4 / 5 = [ 11 xx 2 xx 2 ] / [ 2 xx 9 xx 5 ] = 22 / 45`

\(a,\dfrac{5}{13}\times\dfrac{4}{15}\times13=\dfrac{4}{3}\)

\(b,\left(\dfrac{3}{7}+\dfrac{5}{2}\right)\times\dfrac{7}{5}=\left(\dfrac{6}{14}+\dfrac{35}{14}\right)\times\dfrac{7}{5}=\dfrac{41}{14}\times\dfrac{7}{15}=\dfrac{41}{30}\)

\(c,\dfrac{1}{5}\times\dfrac{11}{18}+\dfrac{11}{18}\times\dfrac{3}{5}=\dfrac{11}{18}\times\left(\dfrac{1}{5}+\dfrac{3}{5}\right)=\dfrac{11}{18}\times\dfrac{4}{5}=\dfrac{22}{45}\)

Gợi ý: Nó trong VBT Toán Nâng Cao

bó tay !

Tham khảo nhé bạn :))

bbbbb

Em nên gõ công thức trực quan để đề bài rõ ràng nhé

a: \(=\dfrac{10-6}{15}\cdot\dfrac{1}{3}=\dfrac{4}{45}\)

b: \(=\dfrac{10+6}{15}\cdot\dfrac{1}{3}=\dfrac{16}{45}\)

c: \(=\dfrac{4+3}{6}\cdot\dfrac{4}{3}=\dfrac{7\cdot4}{6\cdot3}=\dfrac{28}{18}=\dfrac{14}{9}\)

d: \(=\dfrac{20-14}{35}\cdot\dfrac{9}{4}=\dfrac{6}{35}\cdot\dfrac{9}{4}=\dfrac{54}{140}=\dfrac{27}{70}\)

a (2/3 - 2/5 ) nhân 1/3

C1) 

=4/15 x 1/3

= 4/45

C2)

2/3 x 1/3 - 2/5 x 1/3

= 2/9 - 2/15

= 4/45

b (2/3 + 2/5 )nhân 1/3

GIỐNG CÂU A

c (2/3 + 1/2 ) chia 3/4

C1) =7/6 : 3/4

= 14/9

C2) 

2/3 : 3/4 + 1/2 : 3/4

= 8/9 + 2/3

= 14/9

d(4/7 - 2/5 ) chia 4/9

C1) 

= 6/35 : 4/9

= 27/70

C2)

4/7 : 4/9 - 2/5 : 4/9

= 9/7 -9/10

= 27/70

a) C1 : \(\left(\dfrac{2}{3}-\dfrac{2}{5}\right)\times\dfrac{1}{3}=\dfrac{4}{15}\times\dfrac{1}{3}=\dfrac{4}{45}\)

    C2 : \(\left(\dfrac{2}{3}-\dfrac{2}{5}\right)\times\dfrac{1}{3}=\dfrac{2}{3}\times\dfrac{1}{3}-\dfrac{2}{5}\times\dfrac{1}{3}=\dfrac{2}{9}-\dfrac{2}{15}=\dfrac{4}{45}\)

b) C1 \(\left(\dfrac{2}{3}+\dfrac{2}{5}\right)\times\dfrac{1}{3}=\dfrac{16}{15}\times\dfrac{1}{3}=\dfrac{16}{45}\)

    C2 \(\left(\dfrac{2}{3}+\dfrac{2}{5}\right)\times\dfrac{1}{3}=\dfrac{2}{3}\times\dfrac{1}{3}+\dfrac{2}{5}\times\dfrac{1}{3}=\dfrac{2}{9}+\dfrac{2}{15}=\dfrac{16}{45}\)

c) C1 \(\left(\dfrac{2}{3}+\dfrac{1}{2}\right):\dfrac{3}{4}=\left(\dfrac{2}{3}+\dfrac{1}{2}\right)\times\dfrac{4}{3}=\dfrac{7}{6}\times\dfrac{4}{3}=\dfrac{14}{9}\)

   C2 \(\left(\dfrac{2}{3}+\dfrac{1}{2}\right):\dfrac{3}{4}=\left(\dfrac{2}{3}+\dfrac{1}{2}\right)\times\dfrac{4}{3}=\dfrac{2}{3}\times\dfrac{4}{3}+\dfrac{1}{2}\times\dfrac{4}{3}=\dfrac{8}{9}+\dfrac{2}{3}=\dfrac{14}{9}\)

d) C1 \(\left(\dfrac{4}{7}-\dfrac{2}{5}\right):\dfrac{4}{9}=\left(\dfrac{4}{7}-\dfrac{2}{5}\right)\times\dfrac{9}{4}=\dfrac{6}{35}\times\dfrac{9}{4}=\dfrac{27}{70}\)

    C2 \(\left(\dfrac{4}{7}-\dfrac{2}{5}\right):\dfrac{4}{9}=\left(\dfrac{4}{7}-\dfrac{2}{5}\right)\times\dfrac{9}{4}=\dfrac{4}{7}\times\dfrac{9}{4}-\dfrac{2}{5}\times\dfrac{9}{4}=\dfrac{36}{28}-\dfrac{9}{10}=\dfrac{27}{70}\)

cả hai phép = 0

ghi ra

(45-5x9)x1x2x3x4x5x6x7 

= 0         x1x2x3x4x5x6x7

=0

(1+2+3+4+5+6+7+8+9+10)x(72-8x8-8)

=(1+2+3+4+5+6+7+8+9+10)x0

= 0

#Ninh Nguyễn

A) 5/4 x X = 3/8 + 5/12

5/4 x X = 19/24

        X  = 19/24 : 5/4

        X  = 19/30

vậy x =...

B, 3 x 7/10 + 7/10 x 5 + 2 x 7/10

  = 7/10 x ( 3 + 5 + 2)

  = 7/10 x 10

  = 7

Giúp tớ với mọi người ơi