Question 215861
5-6i find the product of the complex number and find its conjugate. 
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Its conjugate is 5+6i.  Only the sign is different between conjugates.
(5-6i)*(5+6i)
= 5*(5+6i) - 6i*(5+6i)
= 25 + 30i - 30i - 36*i*i 
= 25 + 36 (i*i = -1)
= 61
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The product of a complex number and its conjugate,
(a + bi) is always a^2 + b^2