State whether the function y=-2x^2-8x+17 has a maximum or minimum value and identify the coordinates of the vertex.
-2x^2-8x+17
= -2(x^2+4x) + 17
= -2(x^2+4x+4) + 17 + 2*4
= -2(x+2)^2 + 25
Now just read off the vertex.
= -2(x^2+4x) + 17
= -2(x^2+4x+4) + 17 + 2*4
= -2(x+2)^2 + 25
Now just read off the vertex.