What is the axis of symmetry of h(x) = 5x2 + 40x + 64?

For a quadratic h(x) = ax² + bx + c, the axis of symmetry is x = −b/(2a). Here a = 5 and b = 40, so x = −40/(2 × 5) = −4. The axis of symmetry is x = −4, choice B.

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