Ta có: \(5^{n+1}-4.5^n=5^n.5-4.5^n=\left(5-4\right)5^n=5^n\)
CHÚC BẠN HỌC TỐT.........
a) 3x\(^n\) (6x\(^{n-3}\)+1) - 2x\(^n\) ( 9x\(^{n-3}\) - 1)
= 18x\(^{n-2}\) + 3x\(^n\) - 18x\(^{n-2}\) + 2x\(^n\)
= 5x\(^n\)
b) 5\(^{n+1}\) - 4.5\(^n\)
= 5\(^n\) . ( 5-4) = 5\(^n\)