Because this is a positive parabola, it opens upwards, like a cup, and the vertex dictates what the minimum value of the function is. In order to determine the vertex, I recommend completing the square. Do that by first setting the function equal to 0 and then moving the 9 to the other side by subtraction. So far:

. Now, to complete the square, take half the linear term, square it, and add that number to both sides. Our linear term is 6. Half of 6 is 3 and 3 squared is 9. So add 9 to both sides.

. The right side reduces to 0, and the left side simplifies to the perfect square binomial we created while completing this process.

. Move the 0 back over and the vertex is clear now. It is (-3, 0). Therefore, 0 is the minimum point on your graph. The first choice above is the one you want.
Answer: 7x-y=10
Step-by-step explanation:
She had 60 pairs of shoes before selling any
Answer:

Step-by-step explanation:
Since the slope is -5 is either C or D. Let's replace
in either to see what we get.
C:
Nope.
D:
Good!
Answer:
$1030
Step-by-step explanation:
Last winter:
Total expense = 370 * 2.56 = $947.2
Next year,
price increases 9% per gallon
which means, per gallon cost is $2.7904
Approx. expense = 370 * 2.7904 = $1032.448 which is round down to $1030