Respuesta :

the answer will be 3.008 x 10^20
(4.7 x 10^4) by (6.4 x 10^15)

4.7 * 6.4 = 30.08
10^4 * 10^15 = 10^19

so
(4.7 x 10^4) by (6.4 x 10^15)
= 30.08 x 10^19
= 3.008 x 10^20

answer: 3.008 x 10^20 in scientific notation.