\(2^{3x}:2^{x+3}=32\Rightarrow2^{3x-x-3}=2^5\Rightarrow x^{2x-3}=2^5\Rightarrow2x-3=5=>2x=8=>x=4\)

\(2^{5x}:2^{4x}=32\Rightarrow2^{5x-4x}=2^5=>2^x=2^5=>x=5\)

\(\left(x-\frac{1}{2}\right)^3=8=2^3\Rightarrow x-\frac{1}{2}=2\Rightarrow x=2+\frac{1}{2}=\frac{5}{2}\)

=2013.2014-14/2012.2014+2000

=2013.2014-14/2012.2014+2014-14

=2013.2014-14/2014.(2012+1)-14

=2013.2014-14/2014.2013-14

=1

Ti sô tuôi cua bà va me là:

1/4:1/7=7/4

(tu ve so dô)

so tuoi cua me la : 

27:(7-4).4=36 ( tuoi )

so tuoi cua Lan là :

36.1/4-1=8 ( tuoi )

Dap so :8 tuoi

A={1,3,5,....}

B={11,14,17,20,23,26,29}

Bài 1 : 

a)17 . 85 + 15 . 17 -120=17.(85+15)-120=17.100-120=1700-120=1580       

b)75-(3.5^2-4.3^2)=75-(3.25-4.9)=75-(75-36)=75-39=36

c)A=12:{390:[500-(125+35.7)]}

=>A=12:{390:[500-(125+245)]}

=>A=12:{390:[500-370]}

=>A=12:{390:130}

=>A=12:3

=>A=4

d)B=10+12+....+96+98

=>B=(98+10).45

(vi tu 10 den 98 co (98-10):2+1=45)

=>B=108.45

=>B=4860

Bài 2:

a)2.5^2+3:71^0-54:3^3

=2.25+3:1-54:27

=50+3-2

=51

b)189+73+211+127

=(189+211)+(73+127)

=400+200

=600

c)375:{32-[4+(5.3^2-42)]}-14

=375:{32-[4+(5.9-42)]}-14

=375:{32-[4+(45-42)]}-14

=375:{32-[4+3]}-14

=375:{32-7}-14

=375:25-14

=15-14

=1

Bài 3:

a)38.73+27.38

=38.(73+27)

=38.100

=3800

b)5.3^2-32:4^2

=5.9-32:16

=45-2

=43

c)5.2^3+7^11:7^9-1^8

=5.8+7^2-1

=40+49-1

=88

d)400:{5.[360-(290+2.5^2)]}

=400:{5.[360-(290+2.25)]}

=400:{5.[360-(290+50)]}

=400:{5.[360-340]}

=400:{5.20}

=400:100

=4

e)2^3.2^4.2^6

=2^3+4+6

=2^13

(=8192)

f)9^6:3^2

=9^6:9

=9^5

(=59049)