Question

graph y=-x2-8x-17

Answer 1

In google type:
functions graphs online

When you see list of results click on:

rechneronline.de/function-graphs/

When page be open in blue recatacangle type:

-x^2-8x-17

In Display properties set:

Range x-axis from -8 to 2
Range y-axis from -8 to 2

Then click option Draw

You will see graph of your function.

Answer 2

Your function have y-intercept

y= -17

For x=0

y= -x^2-8x-17= -0^2-8*0-17=0-0-17= -17

If you want to see graph with y-intercept in Display properties set:

Range x-axis from -8 to 2
Range y-axis from -18 to 2