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#### karush

##### Well-known member

- Jan 31, 2012

- 2,886

$$f(x)=16x^4+3x^2-2$$

ok I presume we can solve this with the quadratic formula even with powers of 4 and 2

by setting $u=x^2$ I was able to get

$$x=\pm\sqrt{-\frac{3}{2}+\frac{\sqrt{137}}{2}}$$

but $W\vert A$ says the answer is

$$x=\pm\frac{1}{4}\sqrt{-\frac{3}{2}+\frac{\sqrt{137}}{2}}$$

where does the $\frac{1}{4}$ come from?

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