1.\(\dfrac{4}{5}\)

2.\(\dfrac{2}{3}\)

3.\(\dfrac{39}{55}\)

a) \(\dfrac{3}{5}\times\dfrac{2}{3}:\dfrac{1}{2}=\dfrac{3}{5}\times\dfrac{2}{3}\times2=\dfrac{6}{15}\times2=\dfrac{12}{15}=\dfrac{4}{5}\)

b) \(\dfrac{2}{3}\cdot\dfrac{1}{2}+\dfrac{1}{3}=\dfrac{1}{3}+\dfrac{1}{3}=\dfrac{2}{3}\)

c) \(\left(\dfrac{5}{7}+\dfrac{2}{5}\right):\dfrac{11}{7}=\left(\dfrac{25}{35}+\dfrac{14}{35}\right)\cdot\dfrac{7}{11}=\dfrac{39}{35}\cdot\dfrac{7}{11}=\dfrac{273}{385}=\dfrac{39}{55}\)

a) = \(\dfrac{6}{15}\) \(\div\dfrac{1}{2}=\) \(\dfrac{12}{15}\) rút gọn = \(\dfrac{4}{5}\)

b) = \(\dfrac{2}{6}+\dfrac{1}{3}\) = \(\dfrac{6}{18}+\dfrac{6}{18}\) = \(\dfrac{12}{18}\) = \(\dfrac{2}{3}\)

c) = \(\dfrac{5}{7}+\dfrac{2}{5}=\dfrac{25}{35}+\dfrac{14}{35}=\dfrac{39}{35}\) \(\div\dfrac{11}{7}=\dfrac{39}{35}\)

5/2 - 1/4 + 5/3

= 10/4 - 1/4 + 5/3

= 9/4 + 5/3

= 27/12 + 20/12

= 47/12

11/2 : 1/4 x 5/3

= 11/2 x 4/1 x 5/3

= 44/2 x 5/3

= 220/6

= 110/3

14/5 x 2/3 + 5

= 28/15 + 5

= 28/15 + 75/15

= 103/15

nhớ ghi cách giải nha mình tick luôn

*Dấu gạch chéo (/) tượng trưng cho gạch ngang của phân số

a: =11/2*4*5/3

=22*5/3

=110/3

b: =30/12-3/12+20/12

=47/12

c: =28/15+5

=28/15+75/15

=103/15

`a)A=[2\sqrt{3}+2-2\sqrt{3}+2]/[(2\sqrt{3}-2)(2\sqrt{3}+2)]`

   `A=4/[12-4]=1/2`

Với `x > 0,x ne 1` có:

`B=[x-2\sqrt{x}+1]/[\sqrt{x}(\sqrt{x}-1)]`

`B=[(\sqrt{x}-1)^2]/[\sqrt{x}(\sqrt{x}-1)]=[\sqrt{x}-1]/\sqrt{x}`

`b)B=2/5A`

`=>[\sqrt{x}-1]/\sqrt{x}=2/5 . 1/2`

`<=>5\sqrt{x}-5=\sqrt{x}`

`<=>\sqrt{x}=5/4`

`<=>x=25/16` (t/m)

Ai lm đc câu nào thì giúp mk với , cảm ơn !!

\(A=\left|\dfrac{3}{5}-x\right|+\dfrac{1}{9}\ge\dfrac{1}{9}\\ A_{min}=\dfrac{1}{9}\Leftrightarrow x=\dfrac{3}{5}\\ B=\dfrac{2009}{2008}-\left|x-\dfrac{3}{5}\right|\le\dfrac{2009}{2008}\\ B_{max}=\dfrac{2009}{2008}\Leftrightarrow x=\dfrac{3}{5}\\ C=-2\left|\dfrac{1}{3}x+4\right|+1\dfrac{2}{3}\le1\dfrac{2}{3}\\ C_{max}=1\dfrac{2}{3}\Leftrightarrow\dfrac{1}{3}x=-4\Leftrightarrow x=-12\)

a: \(A=\left|\dfrac{3}{5}-x\right|+\dfrac{1}{9}\ge\dfrac{1}{9}\forall x\)

Dấu '=' xảy ra khi \(x=\dfrac{3}{5}\)

GIÚP ĐI XIN ĐÓ AI ĐÓA TRẢ LỜI DÙM CẦN GẤP

x = 28/5-5

x= 3/5

1/3 :3/4 = 1/3 x 4/3= 4/9

\(\dfrac{5}{8}:\dfrac{3}{4}-\dfrac{1}{6}=\dfrac{5}{8}\times\dfrac{4}{3}-\dfrac{1}{6}=\dfrac{5}{6}-\dfrac{1}{6}=\dfrac{4}{6}=\dfrac{2}{3}\)

\(\left(\dfrac{3}{14}+\dfrac{1}{2}\right)\times\dfrac{7}{5}=\left(\dfrac{3}{14}+\dfrac{7}{14}\right)\times\dfrac{7}{15}=\dfrac{10}{14}\times\dfrac{7}{15}=\dfrac{5}{7}\times\dfrac{7}{15}=\dfrac{5}{12}=\dfrac{1}{3}\)

[2x-2=0=>x=1

x-1=0=>x=1

x+1=0=>x=-1

5=0=>x=5

a) ( 42- 6) : 1/2 + 7/6

= 36 : 1/2 + 7/6

= 72 + 7/6

= 439/6

b) 18/5 - 2/7 + 1/3

= 383/105

a) = ( 42 - 6) : 1/2 + 7/6 

= 36 : 1/2 + 7/6

= 72 + 7/6

= 439/6

b) = 18/5 - 2/7 + 1/3

= 116/35 + 1/3

= 383/105

\(a.=\left(42-6\right):\dfrac{1}{2}+\dfrac{7}{6}\)

\(=36:\dfrac{1}{2}+\dfrac{7}{6}\)

\(=\)\(72+\dfrac{7}{6}\)

\(=\dfrac{439}{6}\)

=6/20+13/10

=3/10+13/10

=16/10

=\(\dfrac{77}{50}\)