Respuesta :

(2.5 x 10^-8)(9 x 10^-10) = (2.5 x 9) x (10^(-8 + (-10))) = 22.5 x 10^(-8 - 10) = 2.25 x 10^1 x 10^-18 = 2.25 x 10^(1 + (-18)) = 2.25 x 10^(1 - 18) = 2.25 x 10^-17