You need to solve for s in terms of a, b, and c. The values of a, b, and c can be taken to be arbitrary constants (ie, they don't change, but you also don't know what they are).
You need to solve for s in terms of a, b, and c. The values of a, b, and c can be taken to be arbitrary constants (ie, they don't change, but you also don't know what they are).
No, the OP is asking what is a, b, and c in the quadratic formula. So in the equation
"a" is 1,
"b" is a + b - 2c, and
"c" is ab - ac - bc.