If a polynomial function, f of x , with rational coefficients has roots 3 and square root of 7 , what must also be a root of f of x ?

For a polynomial with rational coefficients, any irrational root involving a square root must occur with its conjugate. Since √7 is a root, −√7 must also be a root. The root 3 is rational, so it does not require −3 to be a root. The correct choice is negative square root of 7.

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