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anonymous
 one year ago
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What is the equation of the quadratic graph with a focus of (−4, 17/8) and a directrix of y = 15/8?
f(x) = −2x^2 + 16x − 24
f(x) = −2x^2 + 15x − 2
f(x) = 2x^2 + 12x − 10
f(x) = 2x^2 + 16x + 34
anonymous
 one year ago
Help will give a medal! What is the equation of the quadratic graph with a focus of (−4, 17/8) and a directrix of y = 15/8? f(x) = −2x^2 + 16x − 24 f(x) = −2x^2 + 15x − 2 f(x) = 2x^2 + 12x − 10 f(x) = 2x^2 + 16x + 34

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@DeltaForce @DecentNabeel @pokamons @AmyRoseRules

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0he word directrix is the clue that we are dealing with a parabola. A parabola is a set of points that are equally distant from the focus (a,b) and the directrix d. So for each point (x,y) on the parabola: (x  a)^2 + (y  b)^2 = (y  d)^2 x^2  2ax + a^2 + y^2  2by + b^2 = y^2  2dy + d^2 Subtract y^2 from both sides... x^2  2ax + a^2  2by + b^2 = 2dy + d^2 Now I would just substitute in the the values (a = 4, b = 17/8, d = 15/8)... x^2  2(4)x + (4)^2  2(17/8)y + (17/8)^2 = 2(15/8)y + (15/8)^2 Simplify... x^2 + 8x + 16  (17/4)y + 289/64 = (15/4)y + 225/64 Add (17/4)y to both sides... x^2 + 8x + 16 + 289/64 = (2/4)y + 225/64 x^2 + 8x + 16 + 289/64 = (1/2)y + 225/64 Subtract 225/64 from both sides... x^2 + 8x + 16 + 1 = (1/2)y x^2 + 8x + 17 = (1/2)y Multiply both sides by 2... 2x^2 + 16x + 34 = y ...which is equal to equation D.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Thanks for the help!

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Romnay said it perfectly, its almost exact to what i would say
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