answersLogoWhite

0

1. The y-intercept of a parabola with equation y = ax^2 + bx + c is c. So, c = -2

2. The vertex is (x, y) = (-4, 2), where x = - b/2a

x = - b/2a

-4 = - b/2a

(-4)(-2a) = (-b/2a)(-2a)

8a = b

So we have:

y = ax^2 + bx + c (substitute what you know: 2 for y, -4 for x, 8a for b, and -2 for c)

2 = a(-4)^2 + (8a)(-4) + (-2)

2 = 16a - 32a - 2

2 = - 16a - 2 (add 2 to both sides)

4 = -16a (divide by -16 to both sides)

-1/4 = a

Since b = 8a, then b = 8(-1/4) = -2 Since a = -1/4, b = -2, and c = -2, then we can write the equation of the parabola as

y = (-1/4)x^2 - 2x - 2.

User Avatar

Wiki User

15y ago

What else can I help you with?

Related Questions

How do you sketch graphs and write equations for parabolas?

If you want to sketch graphs you have to observe the parabola first then find the vertex afterwards you connect them and you've arrived at your answer. In order to write equations for parabolas it has to have x square in it. The standard equation for a parabola is (y - k)2 = 4a(x - h) where h and k are the x- and y-coordinates of the vertex of the parabola and 'a' is a non zero real number. This website at the related link should help, for the equation at least. A parabola is a basic U shaped graph that meets at one point called a vertex. The equation for Andy parabola must have a number being squared such as x2.


An equilateral triangle is inscribed in a parabola with its vertex at the vertex of the parabola how do you find the length of the equilateral triangle?

First you need more details about the parabola. Then - if the parabola opens upward - you can assume that the lowest point of the triangle is at the vertex; write an equation for each of the lines in the equilateral triangle. These lines will slope upwards (or downwards) at an angle of 60°; you must convert that to a slope (using the tangent function). Once you have the equation of the lines and the parabola, solve them simultaneously to check at what points they cross. Finally you can use the Pythagorean Theorem to calculate the length.


Write the equation of the parabola in vertex form vertex 4 3 point 3 5?

So you need something like this: y = a*(x - 4)² + 3. This will make the vertex be at (4,3). Then it looks like you have another point on the parabola (3,5). Plug that in and solve for a. 5 = a*(3-4)² + 3. This becomes 5 = a + 3, so a=2, then the equation is: y = 2*(x - 4)² + 3


How do you write an equation of a line that passes through the xintercep and yintercept?

You can write it either in standard form (ax + by = c) or in slope-intercept form (y = mx + b)


Can you write the equation of a parabola that doesn't cross the x-axis in factored form?

No.


How do you write y equals x minus 4 x plus 2 in vertex form and find the vertex?

The given equation is y = x - 4x + 2 which can be written as y = -3x + 2 This is an equation of a straight line. Therefore it has no vertex and so cannot be written in vertex form.


How do you get Plato web answer key?

find the x-intercepts of the parabola with vertex (7,-12) and y-intercept (0,135). write your answer in this form:(x1,y1),(x2,y2). if necessary, round to the nearest hundredth.


How do you write a sentence using the word vertex?

You just did! Just do this: "How do you write a sentence using the word vertex?" said the student.


How to write an equation that includes the keyword "how to write an equation"?

To write an equation that includes the keyword "how to write an equation," you can use a variable like x to represent the phrase. For example, the equation could be x "how to write an equation."


How do you find the solution of a quadratic equation graphically?

You write the equation in such a way that you have zero on the right side. Then you graph the expression on the left side of the equal sign, and check where it touches the x-axis. Note that this method works for most common equations.


How do you write a rule as an equation?

write a rule as an equation


Tell whether the graph opens up or down Find the coordinates of the vertex Write an equation of the axis of symmetry for the equation y equals 2x2 plus 3x plus 6?

y = 2x2 + 3x + 6 Since a > 0 (a = 2, b = 3, c = 6) the graph opens upward. The coordinates of the vertex are (-b/2a, f(-b/2a)) = (- 0.75, 4.875). The equation of the axis of symmetry is x = -0.75.