Verrry interesting !
In the fraction at the end of the equation ... c/ac ... the numerator
and denominator can both be divided by 'c', and the fraction becomes
1/a .
Then the equation becomes d = a + b + 1/a
The
equation can't be solved for 'c', because there is no relationship
between 'c' and any of the other terms. 'c' can be anything at all, and
it has no effect on anything else in the equation.
Or, to put a finer point on it, 'c' is not a function of 'a', 'b', or 'd' .
