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Which equation represents a parabola with its vertex at (1, –5) and its focus at (1, 0)?

a. 1/20(y+5) = (x-1)^2
b. 20(y+5) = (x-1)^2
c. -20(y+5) = (x-1)^2
d. -1/20(y+5) = (x-1)^2

User SamBuchl
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2 Answers

6 votes

Answer: b. 20(y+5) = (x-1)^2

Step-by-step explanation: just took review

User Akshay Nandwana
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5 votes

Answer:

The equation that represents the parabola is 20(y + 5) = (x - 1)² ⇒ b

Explanation:

The form of the equation of the parabola is (x - h)² = 4p(y - k), where

  • The vertex of the parabola is (h, k)
  • The focus is at (h, k + p)

Let us use the form above to solve the question

∵ The vertex of the parabola is (1, -5)

→ That mean (h, k) is (1, -5)

h = 1 and k = -5

∵ Its focus is at (1, 0)

→ That means (h, k + p) is (1, 0)

k + p = 0

→ Substitute the value of k

∴ -5 + p = 0

→ Add 5 to both sides

∵ -5 + 5 + p = 0 + 5

p = 5

→ Substitute the values of h, k, p in the form above

(x - 1)² = 4(5)(y - -5)

→ Remember that (-)(-) = (+)

∴ (x - 1)² = 20(y + 5)

→ Switch the two sides

20(y + 5) = (x - 1)²

The equation that represents the parabola is 20(y + 5) = (x - 1)²

User Vecta
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