Question

Resolva a equação: 2^x + 2^x-1 = 12

Answer 1

x = 3
pois 
2³ = 8
2³-¹ = 2² = 4
8+4 = 12                ok

Answer 2

2^x + 2^x-1 = 12
2^x + 2^x/2^1 = 12
2^x + 2^x/2 = 12  m.m.c.=2
2.2^x+2^x=2.12
2^x.(2+1)=24
2^x.(3)=24
2^x=24/3
2^x=8
2^x=2^3
x=3