math question?!?!?

Question

2^-n(2^n-2^1+n) i kno the answer is -1 but just cant get it

Answer 1

the first thing to do is the multiply out the brackets

then you need to be aware that when you multiply numbers that have a power to them that the power of each are added together to get a result

so

2^-n x 2^n - 2^-n x 2^(1+n)
to solve look at each part of the equation in turn
2^-n x 2^n = 2^(-n+n) = 2^0 = 1
2^-n x 2^(1+n) = 2^(-n+1+n) = 2^1 = 2

so putting the two parts of the formula back together again

1-2 = -1

QED

Answer 2

There is no answer to this...

2^-n(2^n-2^(1+n)) cannot be solved for n if there is nothing that it is equal to. Or, if you are trying to say, simplify...