2. Tính nhanh

a) A=(\(\dfrac{1}{2}\)- \(\dfrac{7}{13}\)-\(\dfrac{1}{3}\))+(\(\dfrac{-6}{13}\) +\(\dfrac{1}{2}\)+1\(\dfrac{1}{3}\))

b) B = (-1\(\dfrac{1}{2}\):\(\dfrac{3}{-4}\)) .(-4\(\dfrac{1}{2}\)) -\(\dfrac{1}{4}\)

Giúp mình với

Tìm x, biết
a. x + \(\dfrac{3}{10}=\dfrac{-2}{15}\)
b. \(\dfrac{-11}{12}x+0,25=\dfrac{5}{6}\)
c. x + (x+1)+(x+2)+==+(x+2002)=2004

Thực hiện phép tính
a. \(\dfrac{-1}{24}-\left\{\dfrac{1}{4}-\left(\dfrac{1}{2}-\dfrac{7}{8}\right)\right\}\)
b.\(\left(8\dfrac{5}{11}+3\dfrac{5}{8}\right)-3\dfrac{5}{11}\)

c.\(\dfrac{4}{9}:\left(\dfrac{-1}{7}\right)+6\dfrac{5}{9}:\left(\dfrac{-1}{7}\right)\)

d. \(\left(\dfrac{-1}{5}+\dfrac{3}{7}\right):\dfrac{2}{11}+\left(\dfrac{-4}{5}+\dfrac{4}{7}\right):\dfrac{2}{11}\)
M.n giúp mk nha

2. Tính

a) (\(\dfrac{3}{7}\))\(^{21}\) : (\(\dfrac{9}{49}\))\(^6\)

b) 3- (\(-\dfrac{6}{7}\))\(^0\) + (\(\dfrac{1}{2}\))\(^2\) : 2

Giúp mk vs

1. Tìm x \(\in\) Q, biết

a) (x-\(\dfrac{1}{3}\))\(^2\) = 0

b) (x+\(\dfrac{1}{2}\))\(^2\) = \(\dfrac{1}{16}\)

c) (2x-1)\(^3\) = 8

Giúp mk vs

2) Tìm x \in∈ N*

a)27<3x<3.81

b)415.915<2x.3x<1816.216

c)(2x-1)6=(2x-1)8

giúp mình nha, mình đang cần gấp

1)Tìm x biết:

A)\(\left(\dfrac{2}{5}-3x\right)^2=\dfrac{9}{25}\)

B)\(\left(\dfrac{2}{3}x-\dfrac{1}{3}\right)^5=\dfrac{1}{243}\)

2)So sánh:

A)\(5^{222}và\)\(2^{555}\)

B)\(3^{48}và4^{36}\)

Cho biết:

13+23+33+...+103=3025

Tính: a)A=23+43+63+...+203

b) B= 0,53+13+1,53+...+53

Tim tat ca cac so tu nhien n sao cho

a,23.32\(\ge\)2n>16

b,25<5n<625

Tính giá trị biểu thức

\(A=\left(\dfrac{ab}{2}-\dfrac{6ab}{7}\right):\dfrac{5b^2}{14}biết;a=\dfrac{2007}{2010},b=\dfrac{2015}{2016}\)