Posted by madi on Wednesday, January 19, 2011 at 6:37pm.
what is the quadratic function that has the roots (4+3i) and (43i)

algebra 2  Reiny, Wednesday, January 19, 2011 at 7:47pm
there is a fast way to do this using the property
if
ax^2 + bx + c = 0, then
sum or roots = b/a
product of roots = c/a
sum of roots = (4+3i) + (43i) = 8
product of roots = (4+3i)(43i) = 169 = 7
equation:
x^2  8x + 7 = 0
another way is to form the factors:
(x  (4+3i)) and (x  (43i)) and set
(x  (4+3i))(x  (43i)) = 0
(x  4  3i)(x  4 + 3i) = 0
carefully expand, simplify and you will get the above answer.
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