= \(\left(7+7^2+7^3\right)+...+\left(7^{58}+7^{59}+7^{60}\right)\)

= \(7\left(1+7+7^2\right)+...+7^{58}\left(1+7+7^2\right)\)

= \(57.7+...+57.7^{58}\) \(⋮57\)

\(=7\left(1+7+7^2\right)+...+7^{58}\left(1+7+7^2\right)\)

\(=57\cdot\left(1+...+7^{58}\right)⋮57\)

\(\dfrac{16}{27}xX=\dfrac{10}{27}-\dfrac{6}{27}\)

\(\dfrac{16}{27}xX=\dfrac{4}{27}\)

\(X=\dfrac{4}{27}:\dfrac{16}{27}\)

X=\(\dfrac{1}{4}\)

16/27x X+2/9=10/27

16/27x X=10/27-2/9

16/27x X=4/27

X=4/27:16/27

X=1/4

x = 1/4

106 - 57 = (2.5)6 - 56.5 = 26.56 - 56.5=56.(26 - 5)=56.59⋮ 59

52B

53D

54D

55A

56 A

57D

59C

60D

Câu 59

C

Câu 60

D

B

C

D

\(\dfrac{1}{4}\)+\(\dfrac{9}{20}\)

=\(\dfrac{5}{20}\)+\(\dfrac{9}{20}\)=\(\dfrac{5+9}{20}\)=\(\dfrac{14}{20}\)=\(\dfrac{7}{5}\)

\(\dfrac{1}{4}+\dfrac{9}{20}=\dfrac{5}{20}+\dfrac{9}{20}=\dfrac{14}{20}=\dfrac{7}{10}\)

1/4 + 9/20 = 5/20 + 9/20 = 14/20

C gửi tích giúp c nha

sos

sos

sos

sos

sos

Gió nhẹ sang tôi ngỡ trời xuân

4:

a: =>x+2,8=1,5

=>x=-1,3

b: =>5x=-5,05

=>x=-1,01

c: =>-0,6x=-8,844

=>x=14,74

d: =>x^2=1,44

=>x=1,2 hoặc x=-1,2

3:

a: =-8,43+8,43+9,1-9,1=0

b: =18,7-18,7+5,6=5,6

c: =-4,23(19,5+80,5)

=-4,23*100=-423

d:=A*(-2,3+2,3)=0