Final answer:
To multiply (3 + √-16) by (6 - √-64), convert the square roots of negative numbers to imaginary numbers, apply the FOIL method to multiply, and combine like terms. The imaginary units cancel out, leaving a final answer of 50.
Step-by-step explanation:
To multiply (3 + √-16) by (6 - √-64), we first need to simplify the square roots of negative numbers which involve imaginary numbers.
Let's start by simplifying the square roots:
- √-16 = √16 × √-1 = 4i, since √-1 is defined as the imaginary unit, i.
- √-64 = √64 × √-1 = 8i for the same reason as above.
Now, substitute these values back into the original expression and multiply:
- (3 + 4i) × (6 - 8i)
- Use the FOIL method (First, Outside, Inside, Last) to expand the product:
- First: 3 × 6 = 18
- Outside: 3 × (-8i) = -24i
- Inside: 4i × 6 = 24i
- Last: 4i × (-8i) = -32i²
Note that i² = -1, so -32i² becomes +32.
Combine like terms:
- (18) + (-24i) + (24i) + (32)
- The imaginary parts cancel each other out: -24i + 24i = 0
- Final Answer: 18 + 32 = 50