Q&A for How to Simplify Complex Numbers

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  • Question
    What if there's only 1 number for the denominator when it comes to complex numbers? For example: 8 - 3i/-2i? What would the conjugate be for the denominator?
    Technist
    Community Answer
    Here, your denominator has a real number of 0 and a complex number of -2. So what you're really seeing is (8-3i)/(0-2i). So the conjugate would be 0+2i, or simply 2i. You multiply with that and it cancels out the 'i' in the denominator.
  • Question
    How do you simplify an expression like 8(i^60)?
    Alphabet
    Community Answer
    It is known that i^1 = i = sqrt(-1), i^2 = -1, i^3 = -i, and i^4 = 1. Therefore we can split up large exponents like so: 8i^60 = 8 * (i^4)^15 = 8 * (1)^15 = 8.
  • Question
    How to simplify if you have -6i³+i²?
    Orlando Huang
    Community Answer
    You can't sumplify, you can only solve. -6*-i=6i, i^2=-1. 6i+-1=-1+6i. ∴-6i^3+i^2=-1+6i.
  • Question
    How can you simply question like: (-3 + 4i + 2i*8)( 1/2 - 6*9)?
    Bella Johnston
    Community Answer
    When simplifying an equation like this, you need to combine like terms. Like terms are numbers that have the same coefficient (in this case, the letter "i"). So, first should combine like terms (everything with the letter "i"). Therefore, combine 4i + 2i. Now the equation is (-3 + 6i * 8)(1/2 - 6 * 9). Now solve like terms in each set of parenthesis. So the equation is (-24 + 6i)(54.5). Now drop the parentheses (because there are no more like terms in them) and solve! -24 + 6i * 54.5 = 6i * 54.5 - 24 = 6i - 30.5.
  • Question
    Can 28-4i be simplified?
    Donagan
    Top Answerer
    Not really. You can do this: 4(7 - i), but that's all.
  • Question
    If a= -x and b= (-2 + 4i), what is the value of ab^2?
    Community Answer
    ab² = (-x)(-2 + 4i)² = (-x)(-2 + 4i)(-2 + 4i) = (-x)(4 -16i + 16i²) = (-x)(4 -16i -16) = (-x)(-12 -16i) = 12x + 16i x.
  • Question
    Solve -5+5i divided by -2-9i
    I_l1ke_gam3s
    Community Answer
    -5+5i/-2 - 9i. Multiply by the conjugate of the denominator, aka -2 + 9i. Multiply that on the numerator and denominator (-5 + 5i)(-2 + 9i) = 10 - 45i - 10i + 45i^2. 10 - 55i + 45(-1) = 10 - 55i - 45 = -35 - 55i. For the denominator, (-2 - 9i)(-2 + 9i) = 4 -18i + 18i - 81i^2 = 4 + 81 = 85. (-35 - 55i)/85 = -35/85 - 55/85i = -7/17 - 11/17i.
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