Question

tìm x thuộc Z, biết

2^x+2^x+1++2^x+22^x+3-480=0

Answer 1

2^x+2^x.2+2^x.4+2^x.8=480

2^x.(1+2+4+8)=480

2^x.15=480

2^x=32

2^x=2^5

suy ra x=5