a) \(\frac{-1}{3}+\left|\frac{-5}{3}\right|=\frac{-1}{3}+\frac{5}{3}=\frac{4}{3}\)

b) \(\left|\frac{-25}{21}\right|-\left|\frac{-17}{21}\right|=\frac{25}{21}-\frac{17}{21}=\frac{8}{21}\)

Ta có: \(x+y=7\Rightarrow\left(x+y\right)^2=49\Rightarrow x^2+y^2+2xy=49\)

Mà: \(x^2+y^2=25\Rightarrow2xy=24\Rightarrow xy=12\)

\(x^3+y^3=\left(x+y\right)\left(x^2-xy+y^2\right)=7\left(25-12\right)=91\)

(Vì\(x+y=7;x^2+y^2=25;xy=12\))

\(\left(-\dfrac{2}{5}\right)^2\cdot\left|\dfrac{1}{3}-\dfrac{3}{5}\right|-\dfrac{2}{5}\cdot\sqrt{\dfrac{1}{25}}+\dfrac{4}{3}\)

\(=\dfrac{4}{25}\cdot\dfrac{4}{15}-\dfrac{2}{5}\cdot\dfrac{1}{5}+\dfrac{4}{3}\)

\(=\dfrac{16}{375}-\dfrac{2}{25}+\dfrac{4}{3}\)

\(=\dfrac{16}{375}-\dfrac{30}{375}+\dfrac{500}{375}\)

\(=\dfrac{486}{375}=\dfrac{162}{125}\)

d: =-5+9=4

c, = 13 . 29 = 377

d, = 40 : ( -10 ) + 9

= -4 + 9 = 5

c) (38 - 25) . (17 + 12)
= 13 . 29
= 377
d) 40 : (-3 - 7) + 9
= 40 : (-10) + 9
= (-4) + 9
= 5

475 : 25 

= (475 . 4) : (25 . 4)

= 1900 : 100

= 19

\(\dfrac{45.21.25}{7.15.36}=\dfrac{3.3.3.5.7.5.5}{7.5.3.3.2.3.2}=\dfrac{25}{4}\)

45\7 x 21\15 x 25/36

=45x21x25/7x15x36

=15x3x7x3x25/7x15x3x12

=3x25/12

=75/12

=25/4

giúp mik nhé

đi mà giúp đi

e)175:x=345:43

3,4:x=6,8:43

3,4:x=5,1

x=3,4:5,1

x=23

f)x:45 =258:54

x:45=52

x=52×45

x=2

g)(x×0,25+2012)×2013=(50+2012)×2013g)

(x×0,25+2012)×2013=2062×2013

x×0,25+2012=(2062×2013):2013

x×0,25+2012=2062

x×0,25=2062−2012

x×0,25=50

x=50:0,25

x=200

h)(x−12)×53=74−12h)

(x−12)×53=54

x−12=54:53

x−12=34

x=34+12

x=54

1) \(=\left(\frac{3}{5}+\frac{2}{5}\right).\frac{6}{11}\)

\(=1.\frac{6}{11}\)

\(=\frac{6}{11}\)

2)\(\frac{17}{25}.\left(\frac{11}{19}+\frac{6}{19}+\frac{2}{19}\right)\)

\(=\frac{17}{25}.1\)

\(=\frac{17}{25}\)

2.\(\frac{17}{25}.\frac{11}{19}+\frac{17}{25}.\frac{6}{19}+\frac{17}{25}.\frac{2}{19}=\frac{17}{25}\left(\frac{11}{19}+\frac{6}{19}+\frac{2}{19}\right)\\ =\frac{17}{25}.1\\ =\frac{17}{25}\)