a ) 5n+1 - 4 . 5n
= 5.5...(n chữ số 5 ) . 5 - 4 .5n
= 5n( 5 - 4 )
=5n . 1
= 5n
b ) 62 . 64 - 43 ( 36 - 1 )
= 66 - 43 . 36 + 43
= 66 - (22)3 . 36 + 43
= 66 - 26 . 36 + 43
= 66 - 66 + 43
= 43
\(a)5^{n+1}-4.5^n\\ =\left(5-4\right).5^n\\ =1.5^n\\ =5^n\)
\(b)6^2.6^4-4^3\left(3^6-1\right)\\ =6^6-2^6\left(3^6-1\right)\\ =46656-64\left(3^6-1\right)\\ =46656-64.3^6+64\\ =46720-64.729\\ =46720-46656\\ =64\)
Tính giá trị biểu thức:
a) \(5^{n+1}-4.5^n=5^n.5-4.5^n=5^n\left(5-4\right)=5^n.1=5^n\)
b) \(6^2.6^4-4^3\left(3^6-1\right)=6^6-4^3\left(9^3-1\right)=36^3-36^3+4^3=64\)
