Question

c) 4.3^x+2-3^x-1= 963 tìm x

Answer 1

\(4\cdot3^{x+2}-3^{x-1}=963\\ \Leftrightarrow36\cdot3^x-\dfrac{1}{3}\cdot3^x=963\\ \Leftrightarrow3^x=27\\ \Leftrightarrow x=3\)

Answer 2

\(4.3^{x+2}-3^{x-1}=963\\ \Leftrightarrow4.3^2.3^x-\dfrac{3^x}{3}=963\\ \Leftrightarrow3^x.\left(36-\dfrac{1}{3}\right)=963\\ \Leftrightarrow3^x.\dfrac{107}{3}=963\\ \Leftrightarrow3^x=27\\ \Leftrightarrow3^x=3^3\\ \Leftrightarrow x=3\)

Vậy x= 3