Question

The parabola representing a quadratic polynomial f(x) = ax² + bx + c opens upward when ______.

Answer 1

The parabola representing a quadratic polynomial f(x) = ax² + bx + c opens upward when a > 0.

Explanation:

The sign of the leading coefficient a determines the parabola’s concavity, if a > 0 the parabola is concave up (opens upward) and its vertex is a minimum; if a < 0 it is concave down (opens downward).