Final answer:
To multiply 3i and 9i, use the property of complex numbers and simplify using i² = -1. The answer is -27+0i.
Step-by-step explanation:
To multiply 3i and 9i, we can use the property of complex numbers that states that the product of two imaginary numbers can be found by multiplying their coefficients and simplifying with the help of i² = -1.
Therefore, we have:
3i ⋅ 9i = 3 × 9 × i × i = 27 × i² = 27 × (-1) = -27
So, the simplified answer is -27. In the form a+bi, the answer is -27+0i.