a) 892^2 + 892.216 + 108^2
= 892^2 + 2.892.108 + 108^2
= ( 892 + 108 )^2
= 1000^2 = 1000000 




b) 10 , 2.9 , 8 − 9 , 8.0 , 2 + 10 , 2^2 − 10 , 2.0 , 2
= 9 , 8. ( 10 , 2 − 0 , 2 ) + 10 , 2. ( 10 , 2 − 0.2 )
= 9 , 8.10 + 10 , 2.10
= 98 + 102
= 200 







c) 99^3 + 1 + 3 ⋅ ( 99^2 + 99 )
= 99^ 3 + ( 3 ⋅ 99^2 ⋅ 1 ) + ( 3 ⋅ 99 ⋅ 1^2 ) + 1^3
= ( 99 + 1 )^3 = 100^3
= 100000 
mấy bài này giống trong sgk ý nhờ =))