Đáp án:
1) 2^3 - 5^3:5^2 + 12.2^2
= 8 - 5^1 + 12.4
= 8 - 5 + 48
= 51
3) 5.[(85 - 35:7):8 + 90] - 50
= 5 . [ ( 85 - 5 ) : 8 + 90 ] - 50
= 5 . [ 80 : 8 + 90 ] - 50
= 5. [ 10 + 90 ] - 50
= 5. 100 - 50
= 500 - 50
= 450
6) (6^2017 - 6^2016) : 6^2016
= 6^2017 : 6^2016 - 6^2016 : 6^2016
= 6^1 - 6^0
= 6 - 1
=5
7)2^7:2^2+5^4:5^3.2^5
=25+5.16-3.32
=8+5.16-3.32
=8+80-96
=86-96=-10
bn cho mk câu hỏi hay nhất nhá