How do I calculate missing values in an equation

[timhoo]

Hi there, I'm a novice at excel and I am hoping that you guys will be
able to help me.

I'm doing a lab report and I am given this equation:

Q*+Qh+Qe+Qg=0

I have a table with the values of all the Q's (Q*,Qh,Qe,Qg) for each
month. However there is always one value missing in the table, and I am
supposed to use excel to calculate the missing value.

For example:
The month of January, I have the values of: Q*, Qe, Qg; but I do NOT
have the value of Qh. I am supposed to use excel to calculate this
missing value of Qh.

For the month of February, I have the values of: Q*,Qg, Qh, but I do
NOT have the valye of Qe.

To summarize: my question is how can I use excel to calculate these
missing values?

I really hope you guys can help me, I would really appreciate it.

Thanks,
Tim

 

[Roger Govier]

Hi

If you put your known values in A1, B1, C1 and D1, in E1 enter
=0-SUM(A11)