Lesson Worksheet: Multiplying Complex Numbers Mathematics • 12th Grade

In this worksheet, we will practice multiplying two complex numbers.

Q1:

If π‘Ÿ=βˆ’5+2𝑖 and 𝑠=βˆ’8βˆ’2𝑖, find 2π‘Ÿ+3𝑠.

  • Aβˆ’34βˆ’2𝑖
  • B34+2𝑖
  • Cβˆ’34+2𝑖
  • D14+10𝑖
  • E1+10𝑖

Q2:

What is βˆ’7𝑖(βˆ’5+5𝑖)?

  • A35βˆ’35𝑖
  • Bβˆ’35βˆ’35𝑖
  • Cβˆ’35+35𝑖
  • D35+35𝑖

Q3:

Multiply (βˆ’3+𝑖) by (2+5𝑖).

  • Aβˆ’6+5𝑖
  • Bβˆ’6βˆ’18𝑖
  • Cβˆ’1βˆ’13𝑖
  • Dβˆ’6βˆ’8𝑖
  • Eβˆ’11βˆ’13𝑖

Q4:

Simplify (11βˆ’8𝑖)(11+8𝑖)+(13βˆ’6𝑖)(13+6𝑖).

Q5:

If π‘Ÿ=βˆ’2+4𝑖 and 𝑠=8βˆ’π‘–, find (π‘Ÿβˆ’π‘ ).

  • A75βˆ’100𝑖
  • B100+25𝑖
  • C125βˆ’100𝑖
  • Dβˆ’75
  • E100βˆ’75𝑖

Q6:

Find Reο€Ή(7βˆ’2𝑖)ο…οŠ¨.

Q7:

Simplify (3βˆ’6𝑖)(2βˆ’π‘–).

  • Aβˆ’15𝑖
  • Bβˆ’25βˆ’37𝑖
  • C8βˆ’11𝑖
  • Dβˆ’90βˆ’45𝑖
  • Eβˆ’27βˆ’36𝑖

Q8:

If π‘Ÿ=2+𝑖, express π‘ŸοŠ© in the form π‘Ž+𝑏𝑖.

  • A6+7𝑖
  • B2+11𝑖
  • C8+𝑖
  • D11βˆ’2𝑖
  • E8βˆ’π‘–

Q9:

Find the value of 𝑏 such that the complex number (3+4𝑖)(4+𝑏𝑖) is purely imaginary.

Q10:

Solve the equation 𝑖𝑧=βˆ’4+3𝑖.

  • A𝑧=βˆ’4+3𝑖
  • B𝑧=βˆ’3βˆ’4𝑖
  • C𝑧=3+4𝑖
  • D𝑧=βˆ’3+4𝑖
  • E𝑧=3βˆ’4𝑖

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