A complex number in the denominator is eliminated by multiplying the fraction by 1 in the form of the conjugate of that denominator divided by itself.
[tex]\dfrac{13}{-3+2i}=\dfrac{13}{-3+2i}\cdot \dfrac{-3-2i}{-3-2i}=\dfrac{13(-3-2i)}{(-3+2i)(-3-2i)}\\\\=\dfrac{13(-3-2i)}{(-3)^2-(2i)^2}=\dfrac{13(-3-2i)}{9+4}\\\\=-3-2i[/tex]
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A graphing or scientific calculator that handles complex numbers can do this simplification for you.
