Homework Help: Pre-calculus-check answers

Posted by Lucy on Saturday, August 23, 2008 at 1:32pm.

Write the polynomial equation of least degree that has the roots: -3i, 3i, i, and -i.

Answer:
(x+3i)(x-3i)(x-i)(x+i)=x^4+x^3-x^3i+9x^2+9x-9xi-9i

2)Determine if the expression 4m^5-6m^8+m+3 is a polynomial in one variable. If so, state the degree.

Answer: It is a polynomial in one variable; Degree = 8

Thanks

Pre-calculus-check answers - Reiny, Saturday, August 23, 2008 at 2:14pm
your first one would be
(x+3i)(x-3i)(x-i)(x+i) which is what you had, but then
=(x^2 - 9i^2)(x^2 - i^2) remember i^2 = -1
= (x^2 + 9)(x^2 + 1)
= .... you can finish that

your second question is correct

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