-6-7=-13 because you take -2 and 3 you multiply equals-6 than add -7 and it well give you your answer
The area of the room is :

and if the cost is 1.25 per square foot then the total cost will be:

is $340 dollars
The answer should be the directrix because k represents the y-value of the vertex, and for this questions the parabola is probably facing upward, so the directrix is under the vertex.
I believe that is c if I'm wrong I'm very sorry