y=41/45

8/15

m=33/20

21/22 nhé

6/7

21/35 và 20/35 nhé

Câu 1:15/35=3/7

216/270=4/5

250/750=1/3

Câu 2:8/18,12/27,16/36,20/45,24/54

Câu 3:1/2=2/4=3/6=4/8=5/10

Câu 4:2×3×5/2×7×5=30/70=3/7

Tk mình nhé bn!

Bài 1:

\(\frac{15}{35}=\frac{3}{7}\)

\(\frac{216}{270}=\frac{4}{5}\)

\(\frac{250}{750}=\frac{1}{3}\)

Bài 2:

5 phân số bằng phân số \(\frac{4}{9}\) là: \(\frac{8}{18};\frac{12}{27};\frac{16}{36};\frac{20}{45};\frac{24}{54}\)

Bài 3:

\(\frac{1}{2};\frac{2}{4};\frac{3}{6};\frac{4}{8};\frac{5}{10}\)

Bài 4:

\(\frac{2x3x5}{2x7x5}=\frac{3}{7}\)

\(1\)\(\frac{15}{35}\) \(=\)\(\frac{5}{7}\)

\(\frac{216}{270}\)= \(\frac{24}{30}\)

\(\frac{250}{750}\)\(=\)\(3\)

   \(2.\)\(\frac{8}{18}\); \(\frac{12}{27}\)   ; \(\frac{16}{36}\); \(\frac{20}{45}\); \(\frac{24}{54}\)

\(\frac{1}{2}\)=\(\frac{2}{4}\)= \(\frac{3}{6}\)=\(\frac{4}{8}\)=\(\frac{5}{10}\)

4.\(2\cdot3\cdot\frac{5}{2\cdot7\cdot5}\) = \(\frac{3}{7}\)

2: \(=\dfrac{-2}{75}+\dfrac{5}{39}=\dfrac{33}{325}\)

3: \(=\dfrac{6}{11}\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{6}{11}\)

4: \(=\dfrac{7}{19}\left(\dfrac{5}{13}+\dfrac{8}{13}-1\right)=-2\cdot\dfrac{7}{19}=-\dfrac{14}{19}\)

5: \(=\dfrac{2}{7}\left(\dfrac{4}{23}-\dfrac{27}{23}+1\right)=0\)

6: \(=\dfrac{3}{8}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\dfrac{11}{8}=\dfrac{3}{8}+\dfrac{11}{8}=\dfrac{14}{8}=\dfrac{7}{4}\)

b: \(=8+\dfrac{7}{12}-5-\dfrac{3}{8}=3+\dfrac{5}{24}=\dfrac{77}{24}\)

Bài 1:

a) \(x.\dfrac{3}{4}=\dfrac{9}{14}\)

\(\Rightarrow x=\dfrac{9}{14}:\dfrac{3}{4}\)

\(\Rightarrow x=\dfrac{6}{7}\)

b) \(x:\dfrac{5}{9}=\dfrac{3}{10}\)

\(\Rightarrow x=\dfrac{3}{10}.\dfrac{5}{9}\)

\(\Rightarrow x=\dfrac{1}{6}\)

help me

Bài 2:

a) \(\dfrac{3}{10}+\dfrac{2}{5}:\dfrac{4}{15}=\dfrac{3}{10}+\dfrac{3}{2}=\dfrac{9}{5}\)

b) \(\dfrac{4}{7}.3+\dfrac{2}{3}.2=\dfrac{12}{7}+\dfrac{4}{3}=\dfrac{64}{21}\)

                   Đề Bài :\(\frac{9}{14}\)- \(\frac{x}{7}\): \(\frac{5}{3}\)= \(\frac{3}{14}\)

ta có : \(\frac{9}{14}\)- \(\frac{x}{7}\)= \(\frac{3}{14}\)x \(\frac{5}{3}\)= \(\frac{5}{14}\)

          \(\frac{x}{7}\)= \(\frac{9}{14}\)- \(\frac{5}{14}\)= \(\frac{4}{14}\)

         \(\frac{4}{14}\)= \(\frac{x}{7}\)=> \(\frac{4}{14}\)= \(\frac{2}{7}\)=> x = 2

a)-6x=6

x=-1

b)8x=35->x=35/8

c)8|x|=35->|x|=35/2->x=35/2;x=-35/2

mấy ý kia tương tự bạn ạ!

Các bạn giải bài 2 trước đi,  năn nỉ mà!!!

Bài 1:

a)12,5 x (-5/7) + 1,5 x (-5/7)

=-5/7*(12,5+1,5)

=-5/7*14

=-10

b)(-1/4) x (6|2/11) + 3|9/11 x (-1/4)

=-1/4*(68/11+42/11)

=-1/4*10

=-5/2

c tương tự

d)\(\frac{9^8\cdot4^3}{27^4\cdot6^5}=\frac{\left(3^2\right)^8\cdot\left(2^2\right)^3}{\left(3^3\right)^4\cdot\left(2\cdot3\right)^5}=\frac{3^{16}\cdot2^6}{3^{12}\cdot2^5\cdot3^5}=\frac{3^{16}\cdot2^5\cdot2}{3^{16}\cdot3^1\cdot2^5}=\frac{2}{3}\)

Bài 2:

a)Ta có:

2⁸⁰⁰=(2⁸)¹⁰⁰=256¹⁰⁰

8²⁰⁰=(8²)¹⁰⁰=64¹⁰⁰

Vì 256¹⁰⁰>64¹⁰⁰ =>2⁸⁰⁰>8²⁰⁰

b)Ta có:

12⁴⁵=(12³)¹⁵=1728¹⁵

Vì 625¹⁵<1728¹⁵ =>625¹⁵<12⁴⁵

a) -5/7x(12,5+1,5)=-10

b) -1/4x (6I2/11+3I9/11) = -1/4x 10=-5/2

c) (-7/5 + -3/8 + -3/5+5/8): 2009/2010 = -7/4:2009/2010=-1005/574

d)3^16x 4^3/3^12x 6^5=3^4x4^3x6^5=......

bài 2)

2^800=2^4x200= 15^200> 8^200

=> 2^800>8^200

B) quên cách làm

dell   

bai o ban noi the co the ban la c ho day