Question

Tìm x: 

3^{x + 1} + (3^{x + 2} + 4) = 7.2⁴

Answer 1

\(\Rightarrow3^{x+1}+3^{x+2}=7.16-4=108\\ \Rightarrow3^{x+1}\left(1+3\right)=108\\ \Rightarrow3^{x+1}=27=3^3\\ \Rightarrow x+1=3\\ \Rightarrow x=2\)

Answer 2

⇒3^x+1+3^x+2=7.16−4=108

⇒3^x+1(1+3)=108

⇒3^x+1=27=3^3

⇒x+1=3

⇒x=2

vậy x =2