x+\(\frac{1}{2}\)=\(\frac{1}{4}\)+\(\frac{2}{4}\)

x+\(\frac{1}{2}\)=\(\frac{3}{4}\)

x=\(\frac{3}{4}\)-\(\frac{1}{2}\)

x=\(\frac{1}{4}\)

x+\(\frac{1}{2}\)=\(\frac{1}{4}\)+\(\frac{2}{4}\)

x+\(\frac{1}{2}\)=\(\frac{3}{4}\)

x=\(\frac{3}{4}\)-\(\frac{1}{2}\)

x=\(\frac{1}{4}\)k mk mk k lại !!!!! @ ^_^ @

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

\(\frac{28}{x+4}=\frac{36}{63}=\frac{4}{7}\Leftrightarrow\frac{7.28}{7\left(x+4\right)}=\frac{4\left(x+4\right)}{7\left(x+4\right)}\)

=> 4(x+4) = 7.28 

=> 4x + 16 = 196

=> 4x         = 180 

=> x =  4 5 

x/2 + 2/3 nhân x + 3/4 nhân x = 23/12

x nhân (1/2+2/3+3/4) = 23/12

x nhân 23/12 = 23/12

x = 23/12 : 23/12

x = 1

Vậy x = 1

Tk mk nha

X + 3/8=4/3

x          =4/3-3/8

x          =23/24

X x 1/9=21/8

X         =21/8:1/9

X         =7/24

X-5/4=7/6

X       =7/6+5/4

X       =21/8

X:8/3=5

X      =5x8/3

X      =40/3

Duyệt nha!

x+ 3/8=4/3

=>x=4/3-3/8

=>x=20/24=5/6

\(\frac{x}{7}x\frac{4}{9}x5=\frac{3x4x5}{7x9}\)

\(\frac{x}{7}x\frac{4}{9}x5=\frac{20}{21}\)

\(\frac{x}{7}x\frac{4}{9}=\frac{20}{21}:5\)

\(\frac{x}{7}x\frac{4}{9}=\frac{4}{21}\)

\(\frac{x}{7}\)      \(=\frac{4}{21}:\frac{4}{9}\)

\(\frac{x}{7}\)       \(=\frac{9}{21}\) \(=\frac{3}{7}\) 

Vay x la 3

cần tính gọn mà!

\(\left(2.8x-32\right):\frac{2}{3}=90\)

\(2.8\cdot x-32=90\cdot\frac{2}{3}\)

\(\frac{14}{5}x-32=60\)

\(\frac{14}{5}x=60+32\)

\(\frac{14}{5}x=92\)

\(x=\frac{230}{7}\)

B , c , d tương tự

\(\left(1-\frac{1}{3}\right)\times\left(1-\frac{1}{4}\right)\times\left(1-\frac{1}{5}\right)\times\left(1-\frac{1}{6}\right)\times\left(1-\frac{1}{7}\right)\times\left(1-\frac{1}{8}\right)-\frac{1}{4}\times\frac{1}{2}\)

\(=\frac{2}{3}\times\frac{3}{4}\times\frac{4}{5}\times\frac{5}{6}\times\frac{6}{7}\times\frac{7}{8}-\frac{1}{4}\times\frac{1}{2}\)

\(=\frac{2}{8}-\frac{1}{4}\times\frac{1}{2}\)

\(=\frac{2}{8}-\frac{1}{8}=\frac{1}{8}\)

d

Tính A rồi so sánh:

\(\frac{1}{4}\) + \(\frac{1}{9}\) + \(\frac{1}{16}\) + \(\frac{1}{25}\) + \(\frac{1}{36}\) = \(\frac{1769}{3600}\)

3600 chia hết cho 6, nên ta chọn 3600 làm mẫu số chung.

3600 : 6 = 600

\(\frac{5}{6}\) = \(\frac{5\times600}{6\times600}\) = \(\frac{3000}{3600}\)

Mà \(\frac{3000}{3600}\) > \(\frac{1769}{3600}\)

Nên: \(\frac{5}{6}\) > A

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 \(\frac47\)

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

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

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

\(x=10\)