Given the function f of x is equal to negative 5 x squared minus x plus 20 , find f of 3

Substitute 3 for x in f(x) = -5x² - x + 20: f(3) = -5(3²) - 3 + 20. Since 3² = 9, this is -45 - 3 + 20 = -28, so the answer is negative 28.

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