Problem: It is given that one root of 2x2+rx+s=0, with r and s real numbers, is 3+2i(i=−1). The value of s is:
Answer Choices:
A. undetermined
B. 5
C. 6
D. −13
E. 26
Solution:
Since the given equation has coefficients which are real numbers, the second root must be 3-2i. Therefore, the product of the roots, 2S=(3+2i)(3−2i)∴S=26