When you multiply exponents, you just add the exponents together, so 10^2 * 10^3 is 10^5. Then you just multiply the 7.1 and the 5.8, which is 41.18. However, scientific notation should have only 1 digit above the decimal spot, so you make the number smaller from 41.18 to 4.118, so you add 1 exponent to the 10^5.
41.18*10^5 = 4,118*10^6
(EDIT, THE GUY WHO COMMENTED IS CORRECT, SCIENTIFIC NOTATION IS WHEN THE DIGIT IS GREATER THAN 1 OR LESS THAN 10, SO IT WOULD BE 4.118*10^6)
