Adding and Subtracting Complex Numbers

-6i - 2i

• 4i

• - 4i

• - 8i

• 8i

3i - 5i

• 2i

• - 2i

• - 8i

• 8i

You can add and subtract like terms of complex numbers in the same way you add or subtract other like terms.

Try simplifying 4i+5i

• -1i

• 9i

• 20i

• 1i

Answer explanation

To simplify 4i + 5i, combine the coefficients of the like terms: 4 + 5 = 9. Thus, 4i + 5i = 9i. The correct answer is 9i.

What is the sum of 6+3i and 7+12i

• 18+10i

• 13+15i

• 15+13i

• 10+18i

Answer explanation

To add the complex numbers 6+3i and 7+12i, combine the real parts (6+7) and the imaginary parts (3i+12i). This gives 13 for the real part and 15i for the imaginary part, resulting in 13+15i, which is the correct answer.

4i+5i=9i

Just like 4+5=9 or 4x+5x=9x

Now let's try subtraction of imaginary terms

Simplify 4i - 5i

• -1i

• 9i

• 20i

• 1i

Answer explanation

To simplify 4i - 5i, subtract the coefficients: 4 - 5 = -1. Thus, 4i - 5i = -1i. The correct answer is -1i.

(4+7i)+(8-2i)=

• 34i

• 28+6i

• 12+5i

• -4+9i

(5+8i)+(6-10i)

• -1-18i

• 11-2i

• 13-4i

• -20i

(5-2i) + (-7+8i)

• -2+6i

• 12+6i

• -35-16i²

• -35 -16i

(3-2i)-(4-2i)=

• -1+0i

• 7-4i

• 1-2i

• -i

(-9-5i)-(2-7i)

• -40+14i

• -7-12i

• -59i

• -11+2i