Introduction to Complex Numbers

What is (3 - 5i) + (-4 + 7i)?

• -1+2i

• 1+2i

• 7-12i

• -2+3i

What is (-5 + 3i) - (4 + 7i)?

• -1- 4i

• -1+4i

• -9-4i

• -9+4i

If z₁ = 2 + 5i and z₂ = 3 - 2i, what is z₁ × z₂ as a single complex number?

• -4+11i

• 16-19i

• 6-10i

• 16+11i

What is (4 - 5i)(-2 + 7i)?

• 27+18i

• -43+18i

• -43+38i

• 27+38i

What is a complex number?

• A number that can be expressed in the form a + bi, where a and b are real numbers, and i is the imaginary unit.

• A number that can only be expressed in the form a - bi

• A number that has no real part

• A number that can only be expressed in the form a + bi

Answer explanation

A complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is the imaginary unit. This choice correctly defines a complex number.

An imaginary number is also part of which of the following set of numbers?

• Real

• Whole

• Irrational

• Complex

• Rational

A complex number can be expressed as a + bi. What does a represent?

• the real part of the complex number

• the imaginary part of the complex number

• depends on the sign of the number

• the square root of the complex number

A complex number has a real and an ________ part.

• -4

• 4i

• -2

• 2i

In which quadrant is the number –3 + 8i located on the complex plane?

• Quadrant 1

• Quadrant 2

• Quadrant 3

• Quadrant 4