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MathNet 2018-part-05 — 181 problems (EN–VI) Question 115

Math Olympiad Vault · MathNet 2018-part-05 — 181 problems (EN–VI)

Question 115

A real number $a$ satisfies $a^{2}-\frac{1}{2} a=\frac{1}{4}$. What is the value of the expression $a^{3}-\frac{1}{2} a$?

(A) $-\frac{1}{4}$
(B) $\frac{1}{4}$
(C) $\frac{1}{2}$
(D) 4
(E) $\frac{1}{8}$