Perform each operation. Write the answer in standard form.

Question

(−2 + 3𝑖) + (7 − 6𝑖)

(9 + 3𝑖) − (−2 − 7𝑖)

3𝑖(2 − 7𝑖)

Answer 1

These are complex numbers and their standard form is a + bi.

We must treat the a (real) part separately from the bi (imaginary) part.

(−2 + 3𝑖) + (7 − 6𝑖) = (-2 + 7) + (3i - 6i) = 5 - 3i

(9 + 3𝑖) − (−2 − 7𝑖) = (9 - -2) + (3i - -7i) = 11 + 10i

3𝑖(2 − 7𝑖) = 2(3i) - 7i(3i) = 6i - 21i² = -21(-1) + 6i = 21 + 6i