Question

1, tìm x biết

( 3x^2 - 51)^2n = 576^n

Answer 1

(3x² - 51)²ⁿ = 576ⁿ

=> (3x² - 51)²ⁿ = 24²ⁿ = (-24)²ⁿ

\(\Rightarrow\left[\begin{array}{nghiempt}3x^2-51=24\\3x^2-51=-24\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}3x^2=75\\3x^2=27\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x^2=25\\x^2=9\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}\left[\begin{array}{nghiempt}x=5\\x=-5\end{array}\right.\\\left[\begin{array}{nghiempt}x=3\\x=-3\end{array}\right.\end{array}\right.\)

Vậy \(\left[\begin{array}{nghiempt}x=5\\x=-5\\x=3\\x=-3\end{array}\right.\)