To find the zeros of this polynomial, use the transformation `z=x^2` . This means that the polynomial becomes:

`x^4+2x^2-15`

`=z^2+2z-15` factor

`=(z+5)(z-3)` now go back to x

`=(x^2+5)(x^2-3)` the first term has complex roots, the second irrational

`=(x^2+5)(x-sqrt3)(x+sqrt3)`

**The real zeros of the polynomial are `sqrt3` and `-sqrt3` .**

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To find the zeros of this polynomial, use the transformation `z=x^2` . This means that the polynomial becomes:

`x^4+2x^2-15`

`=z^2+2z-15` factor

`=(z+5)(z-3)` now go back to x

`=(x^2+5)(x^2-3)` the first term has complex roots, the second irrational

`=(x^2+5)(x-sqrt3)(x+sqrt3)`

**The real zeros of the polynomial are `sqrt3` and `-sqrt3` .**