a) (-25).21. (-2)2.(-).(-1)2n+1 (n N*)
b) (-5)3. 67. .(-1)2n(n N*)
c) 35. 18 – 5. 7. 28
d) 24. (16 – 5) – 16. (24 – 5)
e) 29. (19 – 13) – 19. (29 – 13)
g) 31. (-18) + 31. ( – 81) – 31
h) (-12).47 + (-12). 52 + (-12)
k) 13.(23 + 22) – 3.(17 + 28)
m) -48 + 48. (-78) + 48.(-21)
n) 135. (171 – 123) – 171. (135 – 123)
p) – (-2009 + 97) – 74. (-18) + 74. (-118) – 2009 – 3
Đáp án:
$\begin{array}{l}
a)\left( { – 25} \right).21.{\left( { – 2} \right)^2}.{\left( { – 1} \right)^{2n + 1}}\\
= – 25.21.4.\left( { – 1} \right)\\
= 25.4.21\\
= 100.21\\
= 2100\\
b){\left( { – 5} \right)^3}.67.{\left( { – 1} \right)^{2n}}\\
= – 125.67.1\\
= – 8375\\
c)35.19 – 5.7.28\\
= 35.\left( {19 – 28} \right)\\
= 35.\left( { – 9} \right)\\
= – 315\\
f)24.\left( {16 – 5} \right) – 16.\left( {24 – 5} \right)\\
= 24.16 – 24.5 – 16.24 + 16.5\\
= – 24.5 + 16.5\\
= 5.\left( { – 24 + 16} \right)\\
= 5.\left( { – 8} \right)\\
= – 40\\
e)29.\left( {19 – 13} \right) – 19.\left( {29 – 13} \right)\\
= 29.19 – 29.13 – 19.29 + 19.13\\
= 13.\left( { – 29 + 19} \right)\\
= 13.\left( { – 10} \right)\\
= – 130\\
g)31.\left( { – 18} \right) + 31.\left( { – 81} \right) – 31\\
= 31.\left( { – 18 – 81 – 1} \right)\\
= 31.\left( { – 100} \right)\\
= – 3100\\
h)\left( { – 12} \right).47 + \left( { – 12} \right).52 + \left( { – 12} \right)\\
= \left( { – 12} \right).\left( {47 + 52 + 1} \right)\\
= \left( { – 12} \right).100\\
= – 1200\\
k)13.\left( {23 + 22} \right) – 3.\left( {17 + 28} \right)\\
= 13.46 – 3.45\\
= 13.45 + 13 – 3.45\\
= 45.\left( {13 – 3} \right) + 13\\
= 45.10 + 13\\
= 450 + 13\\
= 463\\
m) – 48 + 48.\left( { – 78} \right) + 48.\left( { – 21} \right)\\
= 48.\left( { – 1 – 78 – 21} \right)\\
= 48.\left( { – 100} \right)\\
= – 4800\\
n)135.\left( {171 – 123} \right) – 171.\left( {135 – 123} \right)\\
= 135.171 – 135.123 – 171.135 + 171.123\\
= 123.\left( { – 135 + 171} \right)\\
= 123.36\\
= 4428\\
p) – \left( { – 2009 + 97} \right) – 74.\left( { – 18} \right) + 74.\left( { – 118} \right)\\
– 2009 – 3\\
= 2009 – 97 + 74.\left( {18 – 118} \right) – 2009 – 3\\
= \left( {2009 – 2009} \right) – \left( {97 – 3} \right) + 74.\left( { – 100} \right)\\
= – 100 – 7400\\
= 7500
\end{array}$