The axis of symmetry for the graph of the function f of x is equal to 1 fourth x squared plus b x plus 10 is x is equal to 6 What is the value of b ?

For a quadratic function ax² + bx + c, the axis of symmetry is x = −b/(2a). Here a = 1/4, so the axis is x = −b/(1/2) = −2b. Setting −2b = 6 gives b = −3, which is choice A, negative 3.

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