20 POINTS!!! Please please help me. I'm incredibly tired and can't figure this out even though it's a simple equation...

I'm having a problem with step 4. I keep getting -15 but that can't be it, right?

In the box, complete the first 4 steps for graphing the quadratic function given. (Use ^ on the keyboard to indicate an exponent.) Then print a sheet of graph paper and graph the quadratic function to turn in to your teacher. Be sure to label the axes and vertex.
y=−x^2 −4x−3