Adding Subtracting Imaginary and Complex Numbers

Leon is asked to simplify √-120. A good first step would be to...

• divide 120 by 2

• replace the negative with an i on the outside of the radical

• take the square root of -120

• graph y = √-120

The complex conjugate can be found by...

• Changing the sign of both a and b

• Changing the sign of a

• Changing the sign of b

• Switching the a and b values

If you are adding two complex numbers you should

• add all the numbers together then divide by 2

• add only the real numbers and subtract the complex numbers

• add only the complex numbers and subtract the real numbers

• add only the real numbers together and then add only the complex numbers together then stop

The complex conjugate of 4 + 3i is

• 3 + 4i

• 3 - 4i

• 4 - 3i

• 4 + 3i

Solve for x: 

• x = {-4, -1}

• x = {-1, -4}

• x = {2+i, 2-i}

• x = {-2+i, -2-i}

Simplify

(12 - 4i) + (-2 + 8i)

• 8 + 104i

• 10 + 4i

• 14 - 4i

• 10 - 12i

What is the resulting complex number when Z1 and Z2 are added as vectors?

• Z1 + Z2

• Z1 - Z2

• Z2 - Z1

• Z1 * Z2

What is the representation of the complex number 7 + i on an argand diagram?

• 7 units to the right, 1 unit up

• 7 units to the left, 1 unit down

• 7 units to the right, 1 unit down

• 7 units to the left, 1 unit up

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.