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You have a parabola. The x-intercept is (8,0), the y-intercept is (0,0), and the vertex is (4,-3). What is the equation of the parabola?

A) y = (x - 4)^2 - 3
B) y = (x + 4)^2 - 3
C) y = -(x - 4)^2 - 3
D) y = -(x + 4)^2 - 3

User Don Gorgon
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1 Answer

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Final answer:

The correct equation of the parabola with the given x-intercept, y-intercept, and vertex is Option A: y = (x - 4)^2 - 3. The value of 'a' is found by substituting the x-intercept into the vertex form of the equation, yielding a positive coefficient and an upward-facing parabola.

Step-by-step explanation:

The equation of a parabola with a vertex at (4, -3) and the symmetry axis being vertical can be written in the form y = a(x - h)^2 + k, where (h, k) is the vertex of the parabola. Since the vertex is given as (4, -3), we substitute h and k to get the equation y = a(x - 4)^2 - 3. Now, given that one x-intercept is at (8, 0), we can plug these values into our equation to find the value of a. We get:

0 = a(8 - 4)^2 - 3

0 = 16a - 3

16a = 3

a = 3/16

Because the coefficient a is positive, the parabola opens upwards, and since it includes the y-intercept (0,0), the equation could not have a negative coefficient before the squared term, as it would not cross the y-axis there.

Thus, the correct equation of the parabola is Option A: y = (x - 4)^2 - 3, which can be written as y = (3/16)(x - 4)^2 - 3 when the value of 'a' is included.

User Cornelius Qualley
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