SOLUTION: find the complex zeros of the following polynomial. Write f in factored form. f(x)=x^4+x^3+7x^2+9x-18

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: find the complex zeros of the following polynomial. Write f in factored form. f(x)=x^4+x^3+7x^2+9x-18      Log On


   

Question 762012: find the complex zeros of the following polynomial. Write f in factored form.
f(x)=x^4+x^3+7x^2+9x-18
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
find the complex zeros of the following polynomial. Write f in factored form.
f(x)=x^4+x^3+7x^2+9x-18
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Use Rational Roots Theorem
...0...|....1......1......7......9....-18
...1...|....1......2......9.....18......0 (1 is a root)
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....0..|....1......2......9.....18
..-1..|....1......1......8.....10
..-2..|....1......0......9......0 (-2 is a root)
f(x)=(x-1)(x+2)(x^2+9)
x^2+9=0
x=±√-9=±3i
f(x)=(x-1)(x+2)(x+3i)(x-3i)