\(3+\frac{2}{5}-\frac{3}{4}\times\frac{4}{5}\)

\(=3+\frac{2}{5}-\frac{3}{4}\)

\(=\frac{3\times20+2\times4-3\times5}{20}\)

\(=\frac{60+8-15}{20}\)

\(=\frac{68-15}{20}\)

\(=\frac{53}{20}\)

\(5-\frac{7}{9}+\frac{2}{3}-\frac{5}{6}:\frac{4}{9}\)

\(=5-\frac{7}{9}+\frac{2}{3}-\frac{45}{24}\)

\(=\frac{5\times72-7\times8+2\times24-45\times3}{72}\)

\(=\frac{360-56+48-135}{72}\)

\(=\frac{217}{72}\)

a) \(3\frac{4}{7}\times2\frac{4}{5}\)

    \(=\frac{25}{7}\times\frac{14}{5}=\frac{350}{35}=10\)

b) \(\frac{4}{5}:\frac{1}{2}+\frac{17}{3}\)

   \(=\frac{8}{5}+\frac{17}{3}\)

    \(=\frac{109}{15}\)

c) \(5\frac{1}{3}-2\frac{1}{6}\)

  \(=\frac{16}{3}-\frac{13}{6}\)

  \(=\frac{32}{6}-\frac{13}{6}=\frac{19}{6}\)

d) \(4\frac{1}{2}:2\frac{1}{4}\)

  \(=\frac{9}{2}:\frac{9}{4}=\frac{45}{18}\)

a) \(\frac{3}{5}\times y+\frac{1}{2}:\frac{5}{3}-\frac{5}{4}=\frac{1}{2}\times\frac{1}{3}\)

\(\Rightarrow\frac{3}{5}\times y+\frac{3}{10}-\frac{5}{4}=\frac{1}{6}\)

\(\Rightarrow\frac{3}{5}\times y+\left(-\frac{19}{20}\right)=\frac{1}{6}\)

\(\Rightarrow\frac{3}{5}\times y=\frac{67}{60}\)

\(\Rightarrow y=\frac{67}{36}\)

b) \(\frac{4}{5}:y+\frac{1}{4}\times\frac{1}{6}-\frac{1}{2}=\frac{1}{3}\times\frac{5}{2}\)

\(\Rightarrow\frac{4}{5}:y+\frac{1}{24}-\frac{1}{2}=\frac{5}{6}\)

\(\Rightarrow\frac{4}{5}:y+\left(-\frac{11}{24}\right)=\frac{5}{6}\)

\(\Rightarrow\frac{4}{5}:y=\frac{5}{6}+\frac{11}{24}=\frac{31}{24}\)

\(\Rightarrow y=\frac{4}{5}:\frac{31}{24}=\frac{96}{155}\)

c) \(\frac{3}{5}\times y-\frac{4}{5}:3+\frac{1}{12}=\frac{3}{2}+\frac{1}{5}\)

\(\Rightarrow\frac{3}{5}\times y-\frac{4}{15}+\frac{1}{12}=\frac{17}{10}\)

\(\Rightarrow\frac{3}{5}\times y-\frac{4}{15}=\frac{97}{60}\)

\(\Rightarrow\frac{3}{5}\times y=\frac{113}{60}\)

\(\Rightarrow y=\frac{113}{36}\)

\(A=\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}=\frac{77}{60}\)

\(B=\frac{2}{5}X\frac{15}{4}:\frac{5}{16}+\frac{1}{2}=\frac{53}{10}\)

TK NHA

Ai tk mình đi mình bị âm nè mình hứa sẽ k lại!

Cảm ơn trc nha

\(\frac{1}{2}+\frac{1}{2}=\frac{2}{2}=1\)

\(\frac{5}{4}+\frac{5}{4}=\frac{10}{4}=\frac{5}{2}\)

\(\frac{6}{6}+\frac{6}{6}=\frac{12}{12}=1\)

Tk mk vs nha m.n !! ^^

1;2,5;2 kết quả lần lượt

Chịu

Thực hiện phép chịu...

1) \(\frac{4}{5}.\frac{8}{3}.\frac{x}{7}=\frac{96}{105}\)

\(\frac{32.x}{105}=\frac{96}{105}\)

\(32x=96\)

\(x=3\)

Bài 1: Tìm \(x\)

\(\frac45\times\frac83\times\) \(\frac{x}{7}\) = \(\frac{96}{105}\)

\(\frac{32}{15}\) x \(\frac{x}{7}\) = \(\frac{32}{35}\)

\(\frac{x}{7}\) = \(\frac{32}{35}\) : \(\frac{32}{15}\)

\(\frac{x}{7}\) = \(\frac{32}{35}\) x \(\frac{15}{32}\)

\(\frac{x}{7}\) = \(\frac37\)

\(x=\frac37\times7\)

\(x=3\)

b; \(\frac74\times\frac{3}{x}\times\) \(\frac{11}{5}\) = \(\frac{231}{200}\)

\(\frac74\) x \(\frac{3}{x}\) = \(\frac{231}{200}\) : \(\frac{11}{5}\)

\(\frac74\times\frac{3}{x}\) = \(\frac{231}{200}\) x \(\frac{5}{11}\)

\(\frac74\) x \(\frac{3}{x}\) = \(\frac{21}{40}\)

\(\frac{3}{x}\) = \(\frac{21}{40}\) : \(\frac74\)

\(\frac{3}{x}\) = \(\frac{21}{40}\) x \(\frac47\)

\(\frac{3}{x}\) = \(\frac{3}{10}\)

\(x=3:\frac{3}{10}\)

\(x=3\times\frac{3}{10}\)

\(x=10\)

a) Mẫu số chung: 6

\(\frac{1}{2}=\frac{1.3}{2.3}=\frac{3}{6}\) (Dấu . là dấu x nha)

\(\frac{2}{3}=\frac{2.2}{3.2}=\frac{4}{6}\)

Và \(\frac{1}{6}\)

b) Mẫu số chung: 28

\(\frac{4}{7}=\frac{4.4}{7.4}=\frac{16}{28}\)

\(\frac{3}{4}=\frac{3.7}{4.7}=\frac{21}{28}\)

c) Mẫu số chung: 24

\(\frac{5}{4}=\frac{5.6}{4.6}=\frac{30}{24}\)

\(\frac{5}{6}=\frac{5.4}{6.4}=\frac{20}{24}\)

1

a) X=3/5 : 4/5

X=3/4

b) x=2/3 x 2/5

X=4/15

c) x=14/5 : 6/7

X=49/15

d) x=4/9 x 2/3

X= 8/27

2

7/15 < x < 4/3

7/15 < x < 20/15

X = 8/15;9/15;10/15;11/15;12/15;13/15;14/15;15/15;16/15;17/15;18/15;19/15

3

Hai năm nữa tuổi mẹ là

24:(4-1)x4 = 32 (tuổi)

Hai năm nữa tuổi con là

32:4=8 (tuổi)

Năm nay tuổi mẹ là

32-2=30 (tuổi)

Năm nay tuổi con là

8-2=6 (tuổi)

Đáp số tự ghi nhé

1a.\(\frac{3}{4}\)

 b.\(\frac{4}{15}\)

 c.\(\frac{49}{15}\)

 d.\(\frac{8}{27}\)

2. x = 1

3. Mẹ 30 tuổi, con 6 tuổi