290000

học tốt

A = 99^2 + 54.52 + 54.78-1

99.29.101+29 

= 29.(99.101+1) 

= 29(9999+1) 

= 29.10000

= 290000

=93,65 - 350

=-256,35

hoặc là 29 x 36 + 64 x 29 - 350 thì

 = 1044+1856-350

=2900-350

=2550

a,(17-414)-(586-83)

=17-414-586+83

=(17+83)+(-414-586)

=100+(-1000)

=-900

b,29.(-13)+27.(-29)+(-140).(-29)

=(-29).(-1).(-13)+27.(-29)+(-140).(-29)

=(-29).13+27.(-29)+(-140).(-29)

=(-29).(13+27-140)

=(-29).(-100)

=2900

a.  29 .(19 - 13) - 19 - (29 - 13)

= 29 . 6 - 19 - 16

= 174 - 3

= 171

29 . ( 19 - 13 ) - 19 . ( 29 - 13 )

= 29 . 6 - 19 . 6

= 174 - 114

= 60

Ủng hộ nhé ! Bấm Đúng nếu thấy mình trả lời đúng ! 

2 nguoi ra ket qua khac nhau

a: \(\dfrac{5}{13}\left(\dfrac{6}{29}-\dfrac{26}{39}\right)-\dfrac{6}{29}\cdot\left(\dfrac{5}{13}-\dfrac{29}{6}\right)\)

\(=\dfrac{5}{13}\cdot\dfrac{6}{29}-\dfrac{5}{13}\cdot\dfrac{26}{39}-\dfrac{6}{13}\cdot\dfrac{5}{13}+\dfrac{6}{29}\cdot\dfrac{29}{6}\)

\(=\dfrac{-5}{39}\cdot2+1=1-\dfrac{10}{39}=\dfrac{29}{39}\)

b: \(\dfrac{1\cdot198+2\cdot197+3\cdot196+...+198\cdot1}{1\cdot2+2\cdot3+...+198\cdot199}\)

\(=\dfrac{1\left(199-1\right)+2\left(199-2\right)+...+198\cdot\left(199-198\right)}{1\left(1+1\right)+2\left(1+2\right)+...+198\left(1+198\right)}\)

\(=\dfrac{199\left(1+2+...+198\right)-\left(1^2+2^2+...+198^2\right)}{\left(1+2+...+198\right)+\left(1^2+2^2+...+198^2\right)}\)

\(=\dfrac{199\cdot\dfrac{198\cdot199}{2}-\dfrac{198\cdot\left(198+1\right)\cdot\left(2\cdot198+1\right)}{6}}{198\cdot\dfrac{199}{2}+\dfrac{198\left(198+1\right)\left(2\cdot198+1\right)}{6}}\)

\(=\dfrac{3\cdot198\cdot199^2-198\cdot199\cdot397}{6}:\dfrac{3\cdot198\cdot199+198\cdot199\cdot397}{6}\)

\(=\dfrac{198\cdot199\left(3\cdot199-397\right)}{198\cdot199\left(3+397\right)}\)

\(=\dfrac{200}{400}=\dfrac{1}{2}\)

pls mai mình phải nộp rồi

a/-2632

b/-232

c/16

A = 1 3 − 3 4 − − 3 5 + 1 72 − 2 9 − 1 36 + 1 15 = 1 3 − 3 4 + 3 5 + 1 72 − 2 29 − 1 36 + 1 15 = 1 3 + 3 5 + 1 15 − 3 4 − 2 9 − 1 36 + 1 72 = 5 15 + 9 15 + 1 15 − 27 36 − 8 36 − 1 36 + 1 72 = 3 − 1 + 1 72 = 2 + 1 72 = 2 1 72

Tính bằng cách thuận tiện nhất:

\dfrac{1}{4}+\dfrac{2}{5}+\dfrac{3}{4}+\dfrac{3}{5}41​+52​+43​+53​