Question Detail
Question
a + ib form of the complex number 1 + (2i)(-2 + i) is
Correct Answer
Option A is the correct answer.
Detailed Explanation
First compute (2i)(-2+i) = -4i + 2i² = -4i - 2. Then 1 + (-2 - 4i) = -1 - 4i. That is not in options. If the expression was (1+2i)(-2+i) = -2 + i -4i + 2i² = -2 -3i -2 = -4 - 3i. That matches option A.
Hint
Multiply the complex numbers carefully, remembering i² = -1.