want help to substitute all letters in a string at the same time

So I have a string in A1 that goes - (I*B*(E-H*A))/(H*(I*A-H)) and I want to replace or substitute all the letters with their corresponding values in a range.

I need all the A's to be C78, B's to be G71, etc..

As Follows:
A = C78
B = G71
E = G68
H = H66
I = H68

In the end it should look like this - (H68*G71*(G68-H66*C78))/(H66*(H68*C78-H66))

Any efficient ideas on how to accomplish this are much appreciated!

Hi and thank-you for your time and response! Yes I see that will work in this instance but I should have been more specific, what if the Letters aren't always the same?

For example if I wanted to replace a string with letters say in a 'list 1' with values in a 'list 2' how could I do this?

Otherwise I would have to constantly update the code for different instances telling it what to update with what, and that could get old pretty quick haha!

Hi again! I see this is better and can make this work!

However just wondering a bit if there is no simpler way than having to use Replace(Replace(Replace(Replace(Replace( a bunch of times in case one might have a looong list of replacements to make?

Thanks so much!