(5x^3) (-3x^-3)

(5x³)(-3x^-3) = (5)(x³)(-3)(x^-3) = (5)(-3)(x³​)(x^-3) = -15(x^3+(-3)) = -15x⁰ = -15(1) = -15

 

Or you can just write it like this:

 

\(\frac{(5)(x^3)(-3)}{x^3} = (5)(-3) = -15\)