Question

($2^{n+3}$+$2^{n+2}$+$2^{n+1}$+$2^{n}$)=?

Answer 1

2^n(2³+2²+2+1)=2^n(8+4+2+1)=15*2^n
as simple as that!!

Answer 2

2ⁿ⁺³+ 2ⁿ⁺² + 2ⁿ⁺¹ + 2ⁿ =

=  2ⁿ x 2³ + 2ⁿ x 2² + 2ⁿ x 2¹ + 2ⁿ x 1 = 

= 2ⁿ x ( 2³ + 2² + 2¹ + 1) =

= 2ⁿ x ( 8 + 4 + 2 + 1 ) = 

= 15 x 2ⁿ