what is the value of a-b where a and b are constants

Question

The expression x^2-k^2 where k is a constant is equivalent to the expression (x+a)(x-b) where a and b are constants. What is the value of a-b?

Answer 1

x²-k²=(x-k)(x+k)=(x+a)(x-b)=x²+(a-b)x-ab -->a-b=0, a=b.