36Multiplying complex numbers
Write (3 + 2i)(1 − 4i) in the form a + bi.
Multiplying out (3 + 2i)(1 − 4i) with FOIL gives 3 − 12i + 2i − 8i², and since i² = −1, that's 11 − 10i. Check: real part 3(1) + 2(−4)(−1) = 11 ✓.
Write (3 + 2i)(1 − 4i) in the form a + bi.
Multiplying out (3 + 2i)(1 − 4i) with FOIL gives 3 − 12i + 2i − 8i², and since i² = −1, that's 11 − 10i. Check: real part 3(1) + 2(−4)(−1) = 11 ✓.