SOLUTION: Please help me find all the zeros of this function. g(x)= x^4 - 5x^2 - 36

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Question 817709: Please help me find all the zeros of this function. g(x)= x^4 - 5x^2 - 36
Answer by dkppathak(439) About Me  (Show Source):
You can put this solution on YOUR website!
x^4 - 5x^2 - 36 =0
let x^2=t
than x^4=t^2
by substitute
t^2-5t-36=0
by factorization splitting middle term
t^2-9t+4t-36=o
(t-9)(t+4)=0
t=9 or t=-4
again putting t=x^2
x^2=9 or x^2=-4
x=3 0r x=-3 or x=sqr rt 2i or x=squr rt=-sqrrt2i