Question 846532
A){{{h(0)=ab^(0)=1.24}}}
{{{a=1.24}}}
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{{{h(4)=1.24b^4=0.64}}}
{{{b^4=0.64/1.24}}}
{{{b=0.848}}}
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{{{h(t)=1.24(0.848)^t}}}
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Exponential regression data fitting is beyond the scope of this site. 
I used the Hofstra regression equation utility at http://people.hofstra.edu/stefan_waner/realworld/newgraph/regressionframes.html to get
{{{h=1.25406(0.839387)^t}}} with {{{r=-0.985787}}}