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(-15)+17-22+15-17+22=0

5-14+52-4+14-52+4=5

K mình nhé! ^_^

a) -15 + 17 - 22 + 15 - 17 + 22

 = (-15 + 15) + (17 - 17) + (-22 + 22)

= 0 + 0 + 0

=0

b) 5 - 14 + 52 - 4 + 14 - 52 + 4

= 5 + (-14 + 14) + (52 - 52) + (-4 + 4)

= 5 + 0 + 0 + 0

= 5

Chúc bạn học tốt !

cảm ơn cún kì lân đã góp ý nha

72 x 48 + 74 x 48 + 72 x 52 + 28 x 52 

= 48 x ( 72 + 74 ) + 52 x ( 72 + 28 ) = 48 x 146 + 52 x 100 = 7008 + 5200 = 12208

22  nha bn

( - 52 ) + 74 = 22

  ~ hok tốt ~

Bằng 22 nha !!!

a) 75% x X+ 3/4 = 30

              75%x X= 30-3/4

              75%x X=117/4

                        X=117/4 : 75/100

                        X=117/4 x 100/75

                        X= 39

\(a,31.\left(-18\right)+31.\left(-81\right)-31\)

\(=31\left(-18-81-1\right)\)

\(=31\left(-100\right)\)

\(=-3100\)

\(b,13\left(23+22\right)-3\left(17+28\right)\)

\(=299+286-51-84\)

\(=450\)

Cảm ơn

Bài 1:

\(a,A=\left(2+2^2\right)+\left(2^3+2^4\right)+...+\left(2^{2009}+2^{2010}\right)\\ A=\left(1+2\right)\left(2+2^3+...+2^{2009}\right)=3\left(2+...+2^{2009}\right)⋮3\\ A=\left(2+2^2+2^3\right)+...+\left(2^{2008}+2^{2009}+2^{2010}\right)\\ A=\left(1+2+2^2\right)\left(2+...+2^{2008}\right)=7\left(2+...+2^{2008}\right)⋮7\)

\(b,\left(\text{sửa lại đề}\right)B=\left(3+3^2\right)+\left(3^3+3^4\right)+...+\left(3^{2009}+3^{2010}\right)\\ B=\left(1+3\right)\left(3+3^3+...+3^{2009}\right)=4\left(3+3^3+...+3^{2009}\right)⋮4\\ B=\left(3+3^2+3^3\right)+...+\left(3^{2008}+3^{2009}+3^{2010}\right)\\ B=\left(1+3+3^2\right)\left(3+...+3^{2008}\right)=13\left(3+...+3^{2008}\right)⋮13\)

Bài 2:

\(a,\Rightarrow2A=2+2^2+...+2^{2012}\\ \Rightarrow2A-A=2+2^2+...+2^{2012}-1-2-2^2-...-2^{2011}\\ \Rightarrow A=2^{2012}-1>2^{2011}-1=B\\ b,A=\left(2020-1\right)\left(2020+1\right)=2020^2-2020+2020-1=2020^2-1< B\)

đúng rùi

1: =7/2+23/5=35/10+46/10=81/10

2: =6/8+53/8=59/8

3: =43/8+65/7=821/56

\(a,3\dfrac{1}{2}+4\dfrac{3}{5}=\dfrac{81}{10}\\ b,\dfrac{3}{4}+6\dfrac{5}{8}=\dfrac{59}{8}\\ 5\dfrac{3}{8}+9\dfrac{2}{7}=\dfrac{821}{56}\\ 4,4\dfrac{1}{2}-2\dfrac{3}{10}=\dfrac{11}{5}\)

\(\dfrac{93}{17}:x+\left[\dfrac{-4}{17}\right]:x+\dfrac{22}{7}:\dfrac{52}{3}=\dfrac{4}{11}\)

\(=>\left(\dfrac{93}{17}+\dfrac{-4}{17}\right):x+\dfrac{11}{26}=\dfrac{4}{11}\)

\(=>\dfrac{89}{17}:x+\dfrac{11}{26}=\dfrac{4}{11}\)

\(=>\dfrac{89}{17}:x=\dfrac{4}{11}-\dfrac{11}{26}\)

\(=>\dfrac{89}{17}:x=\dfrac{-17}{286}\)

\(=>x=\dfrac{89}{17}:\dfrac{-17}{286}\)

\(=>x=\dfrac{-25454}{289}=-88\dfrac{22}{289}\)

\(\dfrac{93}{17}:x-\dfrac{4}{17}:x+\dfrac{22}{7}:\dfrac{52}{3}=\dfrac{4}{11}\)

\(\Rightarrow\left(\dfrac{93}{17}-\dfrac{4}{17}\right):x+\dfrac{33}{182}=\dfrac{4}{11}\)

\(\Rightarrow\dfrac{89}{17}:x=\dfrac{365}{2002}\)

\(\Rightarrow x=\dfrac{178178}{6205}\)

Ta có: \(\dfrac{93}{17}:x+\dfrac{-4}{17}:x+\dfrac{22}{7}:\dfrac{52}{3}=\dfrac{4}{11}\)

\(\Leftrightarrow\dfrac{89}{17}:x=\dfrac{365}{2002}\)

hay \(x=\dfrac{178178}{6205}\)

(93/17+-4/17) : x + 33/182=4/11

89/17 : x = 4/11 + 33/182

89/17 : x = Sia đề