Find the exponential regression equation for the data points (-4, 0.75), (-2, 6), (3, 28), and (5, 162)

for that, what you need is a calculator... like say a TI(texas instruments) 83 or 83plus or higher, will do regressions, if you have an android device like a phone or tablet, you can also get an app from the play store "Andie's graph", is a TI calculator emulator, it works just like the calculator itself, you'd only need the ROM 

that said, you can also use some online calculators for that.

I could give you a direct link to one, but this site has issues with links, if you do a quick search in google for "keisan exponential regression calculator", it should be the first link, is from the Casio site.

you could do regressions in a spreadsheet as well you could check online for an "addin" or "extension", if you use MS Excel, pretty sure there are some addins for regressions.

if I recall correctly, Excel does regressions natively, but the addins are just frontends, is all, just some added interfacing.

anyhow, if you have an Android device Andie Graph works peachy, I have an 83plus, 84, 86 in it, they all work just like my old TI83plus.

there's also an app in the play store called Graph89, is an emulator for a TI89, the same you need a tiny little file, and texas instruments provides them, have also, works peachy too.