Math subject GRE 3768 problem 19

If you see any mistakes, or have suggestions / alternative methods of solutions that may help people study, please add them to the comments. Good luck with the test, everyone!

[kylebierly]

You can also use the -b/2a trick to find the vertex since you know that'll be the lowest point of the given quadratic equation (whose y values are all positive), sure enough -1/2 is defined on [-3, 0] and an option