If we know that 180-5=128 that means that that equation must be equal to 128.
(2^3x+1)=128
By putting 128 into exponential form with a base of 2 you get 2^7:
(2^3x+1)=2^7
Since these have the same bases we can set the exponents equal to 7. This will give us an exponent of 3x+1=7. By Subtracting across and dividing by 3 you get:
3x=6 to 3/3x = 6/2
This gives us a final answer of:
x=2