câu2
c) 200 - (2x + 6) =4³
200 - (2x + 6) =64
2x + 6 =200 - 64
2x + 6 =136
2x =136 - 6
2x =130
x =130 : 2
x =65
câu3
a)20 : 2² + $5^{9}$ : $5^{8}$
=20 : 4 + $5^{9-8}$
=5 + $5^{1}$
=5 + 5
=10
c,10²- [60 : ($5^{6}$ : $5^{4}$ -3×5)]
=100 - [60 : (5²- 3 × 5)]
=100 - [60 : (5² - 3 x 5)]
=100 - [60 : (25 - 15)]
=100 - [60 : 10]
=100 - 6
=94
cho mik xin hay nhất ạ