Final answer:
The expression 6i - (15-9i) simplifies to -15 + 15i in standard form. Hence the correct answer is option C
Step-by-step explanation:
The expression 6i - (15-9i) can be simplified by distributing the negative sign to both terms inside the parentheses. This gives us: 6i - 15 + 9i.
Next, we can combine like terms by adding the real parts and the imaginary parts separately. In this case, the real parts are -15 and 0, and the imaginary parts are 6i and 9i. So the simplified expression in standard form is -15 + 15i.
Therefore, the correct answer is c. -15 - 3i.
Hence the correct answer is option C