Question

Rút gọn đa thức :

2/3 nhân 3ⁿ+3^n-1

Answer 1

\(\dfrac{2}{3}\cdot3^n+3^{n-1}=\dfrac{2}{3}\cdot3^n+3^n\cdot\dfrac{1}{3}=3^n\left(\dfrac{2}{3}+\dfrac{1}{3}\right)=3^n\cdot3=3^{n+1}\)

Answer 2

\(\dfrac{2}{3}.3^n+3^{n-1}\)=\(\dfrac{2}{3}.3^n+3^n.3^{-3}=\left(\dfrac{2}{3}+\dfrac{1}{3}\right).3^n=3^n\)

Answer 3

mình sưa lại phía dưới là \(3^{-3}thành3^{-1}nhé\)