Question

Find the minimum and maximum value of the function y=−(x−4)^2+9. Enter infinity or -infinity if the function never stops increasing or decreasing.

Answer 1

This is a parabola, and since they gave you the equation in vertex form, you can find the vertex, which will be at (-h, k). The vertex here, then, is at (4, 9).

Since there's a negative sign out in front, we know this parabola opens down, meaning 9 is the highest y value the function will ever reach.

And because this is a parabola, it will just keep going down forever, so the lowest y value it will ever reach is negative infinity.

Answer 2

Nice answer !