Question

2^(x-1) + 2^(x)+ 2^(x+1) – 2^(x+2)+ 2^(x+3)=120

Answer 1

2^(x-1) + 2^(x)+ 2^(x+1) – 2^(x+2)+ 2^(x+3)=120

2^x*2^-1+2^x+2^x*2-2^x*2^2+2^x+2^3=120

2^x(0,5+1+2-2^2+2^3)=120

2^x*7,5=120

2^x=120/7,5

2^x=16

2^x=2^4

x=4