Find the sum. express the answer in scientific notation. (1.54 times 10 superscript 6 baseline) (6.15 times 10 superscript 6 baseline) 7.69 times 10 superscript 6 9.471 times 10 superscript 6 7.69 times 10 superscript 12 9.471 times 10 superscript 12