SOLUTION: find all zeros of the following polynimal. Write the polynimal in factored form. f(x)=x^4+3x^2-40

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: find all zeros of the following polynimal. Write the polynimal in factored form. f(x)=x^4+3x^2-40      Log On


   

Question 836855: find all zeros of the following polynimal. Write the polynimal in factored form.
f(x)=x^4+3x^2-40
Answer by LinnW(1048) About Me  (Show Source):
You can put this solution on YOUR website!
0 =x^4+3x^2-40
0 = (x^2 + 8)(x^2 - 5)
So x^2 + 8 = 0 or x^2 - 5 = 0
Take x^2 + 8 = 0
x^2 = -8
x = sqrt%28-8%29
x = -2sqrt%282%29i or 2sqrt%282%29i
For x^2 - 5 = 0
x^2 = 5
x = -sqrt%285%29 or sqrt%285%29