Determine whether the graph of y = x^2 + 2x − 8 has a maximum or minimum point, then find the maximum or minimum value

Question

anonymous · Answer

@zaynahf  can you please help me?

anonymous · Answer

Just a minute, im getting my notes

anonymous · Answer

Ok do you know which way the parabola is going? Up or down?

anonymous · Answer

i think up because the x^2 is positive

anonymous · Answer

yeah it opens up

anonymous · Answer

Right! So based on that, it tells you whether your vertex will have a maximum or minimum value. When it is opening up (a value is +), there will be a minimum because the vertex is on the bottom, the lowest point of the parabola. When it is opening down (a value is -), there will be a maximum value because the vertex is at the top, the highest point of the parabola. When naming the min/max, you only use the y value of the vertex.
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