You can find out which is the better deal by dividing the price by the amount of ounces available. Here are the unit prices for each answer choice: A (.15), B(.16), C(.12), and D(.15). The cheapest unit price would be the best deal. Thus, the answer is choice C! Hope this helped :))
We will use vertex form of the parabola:
Where (h,k) is the vertex of our parabola. We know that focus and directrix are located at the same distance from the vertex. That distance is a.
We can use this to build a system of equations to calculate a and k. We already know that h=-5, keep in mind that focus and vertex share the same x coordinate.
We just add these two equations together:
We plug this back into the first equation:
That's all the information we need to write down the equation:
None of the answers you provided are correct.
9514 1404 393
Explanation:
Make use of the properties of equality.
a = 2b +6 . . . . . given
a = 9b -8 . . . . . given
2b +6 = 9b -8 . . . . . . . substitution property of equality
6 = 7b -8 . . . . . . . . . . . subtraction property of equality
14 = 7b . . . . . . . . . . . . . addition property of equality
2 = b . . . . . . . . . . . . . . . division property of equality
b = 2 . . . . . . . . . . . . . . symmetric property of equality