Chapter 1 - 1.6 - Other Types of Equations - 1.6 Exercises - Page 128: 5

Solution: $x=0$, $x=3$ and $x=-3$

$6x^4-54x^2=0$ $6x^2(x^2-9)=0$ $6x^2=0$ $x^2=0$ $x=0$ or $x^2-9=0$ $x^2=9$ $x=±3$ Testing: $x=0$: $6(0)^4-54(0)^2=0-0=0$ $x=3$: $6(3)^4-54(3)^2=6(81)-54(9)=486-486=0$ $x=-3$: $6(-3)^4-54(-3)^2=6(81)-54(9)=486-486=0$