a) \(\frac{2}{5}+\left(-\frac{4}{3}\right)+\left(-\frac{1}{2}\right)\)
b) \(\frac{5}{8}-\left(-\frac{2}{5}-\frac{3}{10}\right)\)
c) \(\frac{1}{3}-\left[\left(-\frac{5}{4}\right)-\left(\frac{1}{4}+\frac{3}{8}\right)\right]\)
d) \(\frac{2}{3}-4.\left(\frac{1}{2}+\frac{3}{4}\right)\)
e) \(\left(-\frac{1}{3}+\frac{5}{6}\right).11-7\)
f) \(\left(-\frac{5}{9}\right).\frac{3}{11}+\left(-\frac{13}{18}\right).\frac{3}{11}\)

1,tìm x

a.\(3^x\)=81

b.\(5^{x+2}\)=125

c.\(2^3\)*\(2^{x-1}\)=64

d. 7*\(7^{n+1}\)=343

e.\(\left(x+3\right)^5\)=243

f.\(\left(2x-3\right)^6\)=64

g.\(\left(x-6\right)^3\)=\(\left(x-6\right)^2\)

h.\(\left\{\left[\left(2x+14\right):2^2-3\right]:3\right\}\)-1=0

i.\(\left\{\left[\left(x:3+17\right):10+3\cdot2^4\right]:10\right\}=5\)

2,tính

a.\(7^{3^1}\)         b.\(7^{1^3}\)      c.\(6^{1^{2^{3^4}}}\)       d.\(2017^{2^{0^{1^0}}}\)      e.\(6^3:6^2-6^2:6\)    f.\(\frac{11\cdot2^{22}\cdot3^7-9^{15}}{\left(2\cdot3^{14}\right)^2}\)

\(a.2\left(x-5\right)-3\left(x+7\right)=14\)

\(b.5\left(x-6\right)-2\left(x+3\right)=12\)

\(c.3\left(x-4\right)-\left(8-x\right)=12\)

\(d.-7\left(3x-5\right)+2\left(7x-14\right)=28\)

\(e.5\left(3-2x\right)+5\left(x-4\right)=6-4x\)

\(f.-5\left(2-x\right)+4\left(x-3\right)=10x-15\)

\(g.2\left(4x-8\right)-7\left(3+x\right)=|-4|\left(3-2\right)\)

\(h.8\left(x-|-7|\right)-6\left(x-2\right)=|-8|.6-50\)

cứ từ từ mà giải cũng đc

Tính hợp lý (nếu được)

\(a\) \(19\frac{5}{8}\)\(:\)\(1\frac{5}{7}\)\(-\) \(15\frac{5}{8}\) \(:\) \(\frac{12}{17}\)\(-\)\(1\frac{1}{3}\)

\(b\) \(\frac{2}{5}\)\(.\)\(\frac{1}{3}\)\(-\) \(\frac{2}{15}\)\(:\) \(\frac{1}{5}\)\(+\) \(\frac{3}{5}\)\(.\) \(\frac{1}{3}\)

\(c\)\(\left(3\frac{1}{3}+2,5\right):\left(3\frac{1}{6}-4\frac{1}{5}\right)-\frac{11}{31}\)

\(f\)\(\left(-2\right)^3.\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)

\(g\)\(\left(\frac{2}{5}\right)^2+5\frac{1}{2}.\left(4,5-2\right)+\frac{2^3}{\left(-4\right)}\)

\(h\)\(\frac{4}{9}.19\frac{1}{3}-\frac{4}{9}.39\frac{1}{3}\)

\(k\)\(125\%.\left(\frac{-1}{2}\right)^2:\left(1\frac{5}{16}-1,5\right)+2008^0\)

\(m\)\(F=\frac{1}{18}+\frac{1}{54}+\frac{1}{108}+...+\frac{1}{990}\)

Làm bao nhiêu cũng được nha, càng nhiều càng tốt

Bài 1 : Khối 6 có số học sinh gần 400 em , biết khi xếp hàng 10 ; 12 ; 15 đều thừa 3 học sinh , khi xếp hàng 11 thì vừa đủ . Tính số học sinh khối 6 .

Bài 2 : Tính nhanh :

a ) S = 1 - 2 - 3 + 4 + 5 - ... + 17 - 18

b ) S = 942 - 2567 + 2563 - 1942

c ) S = 1152 - \(\left[374-\left(1152\right)\right]\) + \(\left(-65+374\right)\)

Bài 3 : Tìm x , biết :

a ) 461 + \(\left(x-25\right)\) = 285

b ) 11 - \(\left(-53+x\right)\) = 97

c ) - \(\left(-x+64\right)\) + 113 = - 17

Bài 4 : Tìm x :

a ) \(\left|10-2x\right|\) = 26

b ) \(\left|4x-3\right|\) = 17

c ) \(\left|-x+6\right|\) - 13 = 0

Bài 5 : Tìm x :

a ) \(\left(2x-8\right)\) . \(\left(7-x\right)\) = 0

b ) \(\left(4-x\right)\) . \(\left(3x-57\right)\) = 0

Bài 1: Tính:

A=\(\left(-2\right).\left(-3\right)-5.\left|-5\right|+125.\left(\dfrac{-1}{5}\right)^2\)

B=\(\left(-3\right).\left|-7\right|-\left(-4\right).\left|5\right|+\dfrac{1}{3}.\left|-9\right|\)

C=\(\left(-2\right)^3.\left|-3\right|-\dfrac{1}{5}.\left|-25\right|-4.\left|-7\right|+\left(-2\right)^2\)

D=\(\left(-6\right).\left|-3\right|+2.\left|-9\right|-7\left|\left(-2\right)^3\right|+8.\left|-7\right|\)

E=\(\left|-3^2\right|.\left|4\right|-\left|7\right|.8-\left|6\right|.\left|-8\right|-\left|12\right|.\left(\dfrac{1}{2}\right)^2\)

Bài 2: Tìm x:

a)\(12-2\left|3x+2\right|=10\)

b)\(2.\left|5-4x\right|+17=\left(-2\right)^3.\left(-4\right)\)

c)\(\left|3x-5\right|+\left(-3\right)^2.2=12.\left|3x+5\right|+117\)

d)\(4.\left|3-2x\right|+\left(-5\right).\left|4-3x\right|-5=-6\)

e)\(\left|2x-7\right|-2^3.\left|2x-7\right|+15=-5.\left|2x-7\right|+3\)

f)\(\left|x+2\right|+\left|x^2-4\right|=0\)

g)\(\left|3x-9\right|+\left|x^2-9\right|=0\)

h)\(\left|2x-1\right|+\left|x^2-\dfrac{1}{4}\right|=0\)