Which quadratic function is the standard form of the equation shown?f(x) = x + 8 + 2x + 5x2

Combine the like terms in f(x) = x + 8 + 2x + 5x²: x + 2x = 3x. Then write the terms in standard form, from highest power of x to lowest: f(x) = 5x² + 3x + 8. This matches choice D.

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