How can I find -ve/+ve numbers in a column and then apply a different specific equation for each?

if a is a column of 101 numbers. then

negative number in a= (negative number - c)/d

positive number in a =(positive number-k)/m

and save these values in a new coulmn in ax (at the same orginal order in a)

any one can help me please? plzzzzzzzzzz

Answer 1

[Walter Roberson]

mask = a < 0;
result(mask) = (a(mask) -c)/d;

Answer 2

[Amneh Alshawabka]

Thank u very much