-1930

Vậy là toang rồi,lớp 8,9 cần dùng đấy ;-;

mik lớp 6

776 - { 5. [ 409 - (8.3 - 21²)] - 1724}

= 776 - { 5.[ 409 - (24 - 441)] - 1724}

= 776 - { 5.[ 409 + 417] - 1724}

= 776 - {5. 826 - 1724}

= 776 - 2406

= - 1630 

\(476-\left\{5.\left[409-\left(8.3-21^2\right)\right]-1724\right\}\)

\(=476-\left\{5.\left[409-\left(24-21\right)^2\right]-1724\right\}\)

\(=476-\left\{5.\left[409-3^2\right]-1724\right\}\)

\(=476-\left\{5.\left[409-9\right]-1724\right\}\)

\(=476-\left\{5.400-1724\right\}\)

\(=476-\left\{2000-1724\right\}\)

\(=476-276=200\)

a) 17.(-25) + 25.21

= (-17).25 + 25.21

= 25.[(-17) + 21]

= 25.4

= 100

b) 24.82 + 24.18 - 100

= 24.(82 + 18) - 100

= 24.100 - 100

= 2400 - 100

= 2300

c) (-26) + 48 + (-34) + 42

= [(-26) + (-34)] + (48 + 42)

= (-60) + 90

= 30

d) 476 - {5.[409 - (8.3 - 21)²] - 1724}

= 476 - {5.[409 - (24 - 21)²] - 1724}

= 476 - {5.[409 - 3²] - 1724}

= 476 - {5.[409 - 9] - 1724}

= 476 - {5.400 - 1724}

= 476 - {2000 - 1724}

= 476 - 276

= 200

500 - {5.[409 - (8.3 - 21)² + 10³]} : 15

= 500 - {5.[409 - (24 - 21)² + 1000]} : 15

= 500 - {5.[409 - 3² + 1000]} : 15

= 500 - {5.[409 - 9 + 1000]} : 15

= 500 - {5.[400 + 1000]} : 15

= 500 - {5.1400} : 15

= 500 - 7000 : 15

= 500 - 466

= 34

\(\frac{2^8\cdot3^{21}+2^{18}\cdot3^6}{2^{10}\cdot2^{21}+2^{20}\cdot3^6}=\frac{2^8\cdot3^6\left(3^{27}+2^{10}\right)}{2^{20}\left(2^{11}+3^6\right)}=\frac{3^6\left(3^{27}+2^{10}\right)}{2^{12}\left(2^{11}+3^6\right)}\)

sai đề bạn ơi.Đề đúng là 500 - { 5 . [ 49 -(8.3-21).3 ] } -172

500 - { 5 . [ 49 -(8.3-21).3 ] } -172

=500 - { 5 . [ 49 -(24-21).3 ] } -172

=500 - { 5 . [ 49 -3.3 ] } -172

=500 - { 5 . [ 49-9 ] } -172

=500 - { 5 . 40 } -172

=500 -200-172

=300-172

=128