Maths Excel formula help

[danakajoel]

Hi, apologies, it's been 20 years since my Maths A Level and I'm struggling to rearrange a formula in Excel to solve for a variable. I have:

A = B x C^D + E x C^F

and want to rearrange for C = ...

i.e. with numbers:
368.6 = 100*1.08^2 + 200*1.08^3

but what would it be to calculate 1.08 = ...

I can find C using Goalseek but can't work out how to rearrange the above. I've looked at the various Excel functions and think it may be a straight Math conundrum. Any help appreciated. Thank you

 

[johnnyL]

C = ((A - (E x (C^F))) / B)^(1 / D)

 

[Rick Rothstein]

C = ((A - (E x (C^F))) / B)^(1 / D)

You have not "solved" for C because C appears on both sides of the equation.

 

[Rick Rothstein]

Hi, apologies, it's been 20 years since my Maths A Level and I'm struggling to rearrange a formula in Excel to solve for a variable. I have:

A = B x C^D + E x C^F

and want to rearrange for C = ...

i.e. with numbers:
368.6 = 100*1.08^2 + 200*1.08^3

but what would it be to calculate 1.08 = ...

I can find C using Goalseek but can't work out how to rearrange the above. I've looked at the various Excel functions and think it may be a straight Math conundrum. Any help appreciated. Thank you

The only way you would be able to solve for C is if D equals F, although if D and F are both less than 6, there may be a solution if they are different but calculating it would be quite messy (unless one of them was 1 and the other was 2.)

 

[johnnyL]

Crap, how did I miss that? Apologies to all!

 

[danakajoel]

Sounds like it's unsolvable then! ChatGPT says the same! Dang, surprising as sure there was a way. Thanks for looking all