SAT Math Multiple Choice Question 314: Answer and Explanation
14. If a + bi represents the complex number that results from multiplying 3 + 2i times 5 - i, what is the value of a?
- A. 2
- B. 13
- C. 15
- D. 17
Correct Answer: D
Category: Additional Topics in Math / Imaginary Numbers
Strategic Advice: Multiply the two complex numbers just as you would two binomials (using FOIL). Then, combine like terms and use the definition i2 = -1 to simplify the result.
Getting to the Answer:
The question asks for a in a + bi, so the correct answer is 17.