Question

Multiply and simplify the product. 21(4- 51)

Select the product.
a . -2i
b . 2i
c . -10 + 8i
d .10 + 8i

Answer 1

After multiplying and simplifying the expression 21(4 - 5i), the correct result is 84 - 105i. The answer choices provided do not include the correct answer, so we would need a new option to represent the correct solution.

Step-by-step explanation:

To multiply and simplify the expression 21(4 - 5i), we need to distribute the real number 21 into the complex number in parentheses. We apply the distributive property:

21 * 4 - 21 * 5i

We can now multiply the real parts and the imaginary parts separately:

• 
  
• 21 * 4 = 84
• 
  
• 21 * (-5i) = -105i

Now combine the two results to get the simplified expression:

84 - 105i

None of the answer choices provided, namely a. -2i, b. 2i, c. -10 + 8i, or d. 10 + 8i, is correct. The correct simplified expression of the product is 84 - 105i, so we would need an option 'e' to select the correct answer.