If the graph of f(x)=ax2+bx+c is a parabola that opens downward, what must be true of the value of a?
If the graph of f(x)=ax^2+bx+c is a parabola that opens downward, then the value of a must be negative.
If the graph of f(x) = ax^2 + bx + c is a parabola that opens downward, then the value of "a" must be negative.
To determine the necessary condition for the graph of the quadratic function f(x) = ax^2 + bx + c to open downward, we need to recall that the leading coefficient (the coefficient of the x^2 term) will determine the concavity of the parabola.
In general, if the value of a is positive (+a), the parabola will open upward, and if the value of a is negative (-a), the parabola will open downward.
Therefore, to achieve an opening downward parabola, the value of a must be negative (-a).