Assuming we have two variables x^a and x^b.
If we multiply the two, following the multiplictive rule would be
x^[a+(-b)] = x^(a-b)

No. Ιt's multiplication, we sum exponents in this case.

x^a * x^b=x^(a+b), and therefore if a=b, then x^a * x^b= x^2a (or x^2b)

This example you used works in case we divide those variables x^a and x^b (or you probably forgot the minus sign on the b exponent).

Regardless, upvoted. Good job!