16=ab^(-3) and
4=ab^(-1)
remember
(x^m)/(x^n)=x^(m-n)
also
x^-m=1/(x^m)
divide first equation by 2nd
16/4=(ab^(-3))/(ab^(-1))
4=b^(-3-(-1))
4=b^(-3+1)
4=b^(-2)
4=1/(b^2)
times both sides by b^2
4b^2=a
divide both sides by 4
b^2=1/4
sqrt bth sides
b=1/2
sub back
4=ab^-1
4=a(1/2)^-1
4=a(1/(1/2))
4=a(2)
divide both sides by 2
2=a
the funtino is
[tex]y=2( \frac{1}{2})^x [/tex]
