The imaginary number <em>i</em> signifies the imaginary part of a complex number. The imaginary part of the number is the coefficient of <em>i</em>. The real part is everything else.
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In (a +bi), (a) is the real part, and (b) is the imaginary part.
In (-9 +8i), (-9) is the real part and (8) is the imaginary part.
