Given that the directrix is at y = 4 and the focus is at (0, -4), then the vertex is at (h, k) = (0, 0).
p is the distance between the vertex and the focus and between the vertex and the directrix = 4 and since the focus is below the directrix, p is negative, i.e. p = -4
Equation of a parabola is given by (x - h)^2 = 4p(y - k)
Therefore, the required equation is (x - 0)^2 = 4(-4)(y - 0)
x^2 = -16y
y = -1/16 x^2
Answer:
19. c 20.b
Step-by-step explanation:
Step-by-step explanation:
here's the answer to your question
Answer:
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Step-by-step explanation:
Answer: $20.5
Step-by-step explanation:
Let x denotes the amount for total bill.
We are given that , Sierra left $4.50 as a tip for a waiter.
This was 18% of the bill before the tip.
We can write 18% = 0.18. [To convert percent into decimal we divide it by 100.]
Then, the tip amount = 0.18 x Total bill
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So, the total bill amount = $25
Hence, her total bill before the tip= Total bill amount - Tip amount
= $25- $4.50=$20.5
Thus ,her total bill before the tip= $20.5