MizoriesKun 4^(x+2)+4^(x+1)=320
4^(x+1)*(1+4)=320
4^(x+1) = 64
4^(x+1)=4^3
x+1=3
x=2

mmb1

Verified answer

4^(x+2)+4^(x+1)=320
16*4^(x )+4*4^(x)=320
20*4^(x )=320
4^(x )=320/20
4^(x )=16
х=2