Question

equação exponencial 2x+1+2x+3=20

Answer 1

$2^{x+1}\,+\,2^{x+3}=20 \\ \\ 2^x\cdot2^1 + 2^x\cdot2^3=20 \\ \\ 2^x\cdot2 + 2^x\cdot8 = 20 \\ \\ 2^x\cdot(2+8)=20 \\ \\ 2^x\cdot10=20 \\ \\ 2^x= \frac{20}{10} \\ \\ 2^x=2^1 \\ \\ \boxed{x=1}$