ai giúp em với ;(9huhu k 2

a) 12/15 rút gọn cho 3 bằng 4/5          

b) 20/15 rút gọn cho 5 bằng 4/3

c)36/24 rút gon cho 6 bằng 6/4 lại rút gọn tiếp cho 2 bằng 3/2

d) 2/4 rút gọn cho 2 bằng 1/ 2

e) 6/8 rút gọn cho 2 bằng 3/4

g) 4/10 rút gọn cho 2 bằng 2/ 5 .

Đáp án là như vậy k cho mình nha !!!

ai giúp em đi.em k 2 cái lunnn

A) \(\dfrac{5}{10}-\dfrac{2}{15}\)

\(=\dfrac{1}{2}-\dfrac{2}{15}\)

\(=\dfrac{15}{30}-\dfrac{4}{30}\)

\(=\dfrac{11}{30}\)

B)\(\dfrac{5}{20}-\dfrac{1}{6}\)

\(=\dfrac{1}{4}-\dfrac{1}{6}\)

\(=\dfrac{6}{24}-\dfrac{4}{24}\)

\(=\dfrac{2}{24}=\dfrac{1}{12}\)

C) \(\dfrac{6}{18}-\dfrac{6}{24}\)

\(=\dfrac{1}{3}-\dfrac{1}{4}\)

\(=\dfrac{4}{12}-\dfrac{3}{12}\)

\(=\dfrac{1}{12}\)

D) \(\dfrac{5}{9}-\dfrac{3}{12}\)

\(=\dfrac{5}{9}-\dfrac{1}{4}\)

\(=\dfrac{20}{36}-\dfrac{9}{36}\)

\(=\dfrac{11}{36}\).

a: =1/2-2/15

=15/30-4/30

=11/30

b: =1/4-1/6

=3/12-2/12

=1/12

c: =1/3-1/4

=1/12

d: =20/36-9/36

=11/36

1.

a, Ta có 28=14⇒14+56=1312(Bn tự quy đồng lên nhé !)

b,Ta có1216=34⇒18+34=78(Bn tự quy đồng lên nhé !)

c,Ta có636=16⇒14+16=512(Bn tự quy đồng lên nhé !)

d,Ta có1218=23⇒23+14=1112(Bn tự quy đồng lên nhé !)

7.Phần này mk chỉ cho đáp án thuia.67     ;     

 b,420=15     ;         

c,615       ;            

d,129

 Help me

a) 2/5 : 2/3 = 2*3/5*2 = 3/5                         b) 4/7 : 4/5 = 4*5/7*4=5/7

c)1/6 : 1/3 = 3/6=1/2                            d) 1/4 : 1/8 = 8/4=2

a) \(\frac{2}{5}:\frac{2}{3}=\frac{2}{5}.\frac{3}{2}=\frac{6}{10}=\frac{3}{5}\)

b) \(\frac{4}{7}:\frac{4}{5}=\frac{4}{7}.\frac{5}{4}=\frac{20}{28}=\frac{5}{7}\)

c)\(\frac{1}{6}:\frac{1}{3}=\frac{1}{6}.\frac{3}{1}=\frac{3}{6}=\frac{1}{2}\)

\(\frac{1}{4}:\frac{1}{8}=\frac{1}{4}.\frac{8}{1}=\frac{8}{4}=2\)

hok tốt!!

Bài 2.

a) 101³ = (100+1)³ = 100³+3.100².1+3.100.1²+1³ 

   = 1000000+30000+300+1 = 1030301

b) 299³ = (300-1)³ = 300³-3.300².1+3.300.1²-1³

   = 27000000 - 270000 + 900 -1 = 26730899

c) 99³ = (100-1)³ = 100³-3.100².1+3.100.1²-1

   = 1000000 - 30000 + 300 -1 = 970299

\(1,\\ b,A=\left(u-v\right)^3+3uv\left(u+v\right)\\ A=u^3-3u^2v+3uv^2-v^3+3u^2v+3uv^2=u^3-v^3\\ c,6\left(c-d\right)\left(c+d\right)+2\left(c-d\right)^2-\left(c-d\right)^3\\ =6c^2-6d^2+2c^2-4cd+2d^2-c^3+3c^2d-3cd^2+d^3\\ =8c^2-c^3-4d^2-4cd+3c^2d-3cd^2+d^3\)

\(2,\\ a,101^3=\left(100+1\right)^3\\ =100^3+3\cdot10000\cdot1+3\cdot100\cdot1+1\\ =1000000+30000+300+1=1030301\\ b,299^3=\left(300-1\right)^3\\ =300^3-3\cdot90000\cdot1+3\cdot300\cdot1-1\\ =27000000-270000+900-1\\ =26730899\\ c,99^3=\left(100-1\right)^3\\ =100^3-3\cdot10000\cdot1+3\cdot100\cdot1-1\\ =1000000-30000+300-1=970299\)

Bài 1:
a.

$A=u^3-3u^2v+3uv^2-v^3+3uv^2+3u^2v$

$=u^3+6uv^2-v^3$

c.

$C=(c-d)[6(c+d)+2(c-d)-(c-d)^2]$

$=(c-d)[8c+4d-(c^2-2cd+d^2)]=(c-d)(-c^2+2cd-d^2+8c+4d)$

bạn viết thế này khó nhìn quá

nhìn hơi đau mắt nhá bạn hoa mắt quá

a. A = (a + b)³ - (a - b)³

A = \(\left[\left(a+b\right)-\left(a-b\right)\right]\left[\left(a+b\right)^2+\left(a+b\right)\left(a-b\right)+\left(a-b\right)^2\right]\)

A = (a + b - a + b)\(\left[a^2+2ab+b^2+a^2-b^2+a^2-2ab+b^2\right]\)

A = 2b(a² + a² + a² + 2ab - 2ab + b² - b² + b²)

A = 2b(3a² + b²)

A = 6a²b + 2b³

a) \(\dfrac{5}{6}-\dfrac{2}{14}\)

\(=\dfrac{5}{6}-\dfrac{1}{7}\)

\(=\dfrac{35}{42}-\dfrac{6}{42}\)

\(=\dfrac{29}{42}\)

b) \(\dfrac{5}{20}-\dfrac{1}{6}\)

\(=\dfrac{1}{4}-\dfrac{1}{6}\)

\(=\dfrac{3}{12}-\dfrac{2}{12}\)

\(=\dfrac{1}{12}\)

c) \(\dfrac{5}{9}-\dfrac{3}{12}\)

\(=\dfrac{5}{9}-\dfrac{1}{4}\)

\(=\dfrac{20}{36}-\dfrac{9}{36}\)

\(=\dfrac{11}{36}\)

d) \(8-\dfrac{4}{6}\)

\(=\dfrac{48}{6}-\dfrac{4}{6}\)

\(=\dfrac{44}{6}=\dfrac{22}{3}\).