solve the polynomial inequality

(1) x4 - 5x2 + 4 < 0

(2) x4- 2x2 - 63 < or = 0

(2)

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1. x4 - 5x2 + 4< 0

= x4 - 4x2 - 1x2 +4 < 0

= x2( x2 - 4) -1(x2 -4) < 0

= x2 - 1 <0 , x2 -4 <0

= x < root 1 , x < root 4

x<1, x<2

2. x4 - 2x2 - 63 < or = 0

= x4 - 9x2 +7x2 - 63< or = 0

= x2( x2-9) + 7 ( x2-9) < or = 0

=x2 +7 < or = 0, x2-9 < or = 0

= x <or = root 7, x <or = root 9

x<or = root 7, x<or = 3

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