Simplication of Equation

Question

input: (a+b)-(c-d)+f output: a+b-c+d+f

Answer 1

When you will open the parentheses to calculate beacuse of the - minus sign in front of second parentheses. c will become - minus and d will be in +. Which will lead to the results like you mentioned in the question. You can use Bodmas rule here.

Answer 2

parentheses has more priority than any other operants..
first solve parentheses and other
(a+b)
(c-d)
then solve