đc mây điểm zậy bạn

chia buồn

tick cho mk nha

Ta co

\(3^{n+2}-2^{n+4}+3^n+2^n=3^n.3^2-2^n.2^4+3^n+2^n=3^n.\left(3^2+1\right)-2^n.\left(2^4-1\right)=3^n.10-2^n.15=5.\left(3^n.2-2^n.3\right)=5.2.3.\left(3^{n-1}-2^{n-1}\right)=30.\left(3^{n-1}-2^{n-1}\right)\)

Vì 30 chia hêt cho 30 nên 30.(\(3^{n-1}-2^{n-1}\)) chia hêt cho 30

Hay \(3^{n+2}-2^{n+4}+3^n+2^n\) chia hêt cho 30

Ta co \(x^4=\left(\dfrac{1}{4}\right)^2\)

\(=>x^4=\dfrac{1}{16}\)

\(=>x^4=\left(\dfrac{1}{2}\right)^4\)

\(=>x=\dfrac{1}{2}\) hoặc \(\dfrac{-1}{2}\)

Vậy x ={\(\dfrac{-1}{2};\dfrac{1}{2}\)}

tick cho mk nha