Answer
$x=-3, 3, -2i, 2i$
Work Step by Step
$x^4-5x^2-36=0$
$(x^2+4)(x^2-9)=0$
$(x^2+4)(x-3)(x+3)=0$
$x^2+4=0$
$x^2=-4$
$\sqrt {x^2}=\sqrt {-4}$
$x=\sqrt{-1*4}$
$x=\sqrt{-1*2^2}$
$x=2\sqrt{-1}$
$x=±2i$
$x-3=0$
$x=3$
$x+3=0$
$x=-3$
Algebra: A Combined Approach (4th Edition)
by Martin-Gay, Elayn
Published by
Pearson
ISBN 10:
0321726391
ISBN 13:
978-0-32172-639-1
Chapter 11 - Section 11.3 - Solving Equations by Using Quadratic Methods - Practice - Page 782: 3
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