Question 190698
5x^4 + 14x^2 - 3 = 0
This is a quadratic in x^2.  Use the quadratic equation to find 2 zeroes for x^2, then get the sqrt of those.
(5x^2 - 1)*(x^2 + 3) = 0

x^2 = 1/5
x = +sqrt(5)/5
x = -sqrt(5)/5
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x^2 = -3
x = +3i
x = -3i
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x^2 + 3 = 0
*[invoke solve_quadratic_equation 1,0,3]