What is #(2^(x+4) - 2(2^x))/(2*(2^(x+3))#?

1 Answer
Dec 16, 2015

I found #1/8#

Explanation:

Here we can use a wide collection of rules of exponents such as:
#2^x*2^y=2^(x+y)#
#2^x/2^y=2^(x-y)#
and write it as:
#(2^(x+4)-2^1*2^x)/(2^1*2^(x+3))=#
#=(2^(x+4)-2^(x+1))/(2^(x+3+1))=#
#=(2^(x+4)-2^(x+1))/(2^(x+4))=#
you can write:
#=2^(x+4)/(2^(x+4))-(2^(x+1))/(2^(x+4))=#
use the second property to write:
#=2^(x+4-x-4)-2^(x+1-x-4)=#
#=2^0-2^-3=1-1/2^3=1-1/8=7/8#