Hi, I am beginner in mathematics , I have the following three relationships:
I need to calculate c under the assumption that a, b and d are known values.
I got c=a-b+d
can I use any other formulas?!!
c=a/b*d is not true.
Unless you mean
That is generally not true but given your conditions...
If it ain't broke, fix it until it is.
A number by itself is useful, but it is far more useful to know how accurate or certain that number is.