Question

2的(x-1)次幂+2的(x-2)次幂+2的(x-3)次幂=488解方程

Answer 1

2^(x-1)+2^(x-2)+2^(x-3)

=2^2*2^(x-3）+2*2^(x-1)+2^(x-3)

=2^(x-3)*(4+2+1)=448

2^(x-3)=448/7=64

2^6=64

x-3=6

x=9