Final answer:
To simplify the expression 7 + 3 - 4j + 9, combine the like terms (7, 3, 9) to get 19, and write -4j as is because it contains a variable. The simplified expression is 19 - 4j, which means the correct answer is none of the options provided.
Step-by-step explanation:
To simplify the expression 7 + 3 - 4j + 9 by combining like terms, we first identify the like terms. Numbers without variables are like terms, and so are numbers with the same variable. In this case, 7, 3, and 9 are like terms and can be combined. The term -4j is different because it includes a variable 'j' and cannot be combined with the numbers. Adding up the like terms, we get 7 + 3 + 9 = 19. So, the simplification of the expression is 19 - 4j. This does not match any of the options provided, so our answer is: none of the above.
We check if our answer is reasonable by reviewing the combination of like terms. Since we correctly combined only the constants (numbers without variables), the answer of 19 - 4j is indeed reasonable.