Question

Multiply:

(14i)(2−4i). Give your answer in the form a+bi.

a. −56−28i
b. −8+28i
c. −8−28i
d 56−28i

Answer 1

To multiply the complex numbers (14i)(2-4i), use the distributive property and combine the real and imaginary parts of the result. The correct answer is -56-28i. Hence, a) is correct.

Step-by-step explanation:

To multiply complex numbers, such as (14i)(2-4i), you can use the distributive property.

First, multiply the real parts of the numbers: 2 * 0 = 0. Then, multiply the imaginary parts: 2 * -4i = -8i.

Next, multiply the imaginary part of the first number with the real part of the second number: 14i * 2 = 28i.

Finally, multiply the imaginary parts of both numbers: 14i * -4i = -56.

Combining all these results, the final answer is 0 + (-8i) + 28i + (-56) = -56 - 28i.

Therefore, the correct answer is (a) -56-28i.