A real number x is such that the sum of the number and four times its square is the <strong>LEAST</strong>. What is that number?

Explanation

Let the number be x. The sum is the quadratic function f(x) = 4x^2 + x. The minimum value of a quadratic ax^2+bx+c occurs at x = -\frac{b}{2a}. Thus, x = -\frac{1}{2 \times 4} = -\frac{1}{8} = -0.125.

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