Form a third degree polynomial function with real coefficients such that 7+i and 6 are zeros
If 7 + i is a zero, then so is 7 - i
So we have
( x - (7 + i) ) ( x - (7 + i)) ( x -6)
[ x^2 - (7 - i)x - (7 + i)x + ( 7 + i) ( 7 - i)] ( x - 6)
[ x^2 -7x + ix - 7x -ix + 49 - i^2 ] ( x - 6)
[ x^2 - 14x + 49 - (-1) ] ( x - 6)
(x^2 - 14x + 50) ( x - 6)
x^3 - 14x^2 + 50x
-6x^2 + 84x - 300
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x^3 - 20x^2 + 134x - 300