Study the expression (x+y+z)2−(x−y+z)2 where x,y, and z are real numbers.
a. (i) Expand both squares completely.
b. (ii) Simplify the result obtained in part (i) and write it in its lowest form.
c. (iii) Calculate the value of the simplified expression for x=3, y=1, and z=−2. Show all intermediate steps.