Question 1182936
Part (b), probably not the way you expect to solve but there are two points and from them  {{{system(12=ab^(-3),3=ab^(-1))}}}.

Dividing one equation by the other,.... {{{b=1/2}}}, and using this in second equation,...  {{{a=3/2}}}.


Equation for your points, {{{y=(3/2)(1/2)^x}}}.