# Pre-calc

1. Find the equation for a quadratic function whose vertex is (2,5) and whose graph contains the point (-8,15).

2.What are the x- and y- intercepts for y=2x^2+x-6

Plesee explai. I want to learn to learn how to do them.

1. 👍 0
2. 👎 0
3. 👁 314
1. The standard form of a quadratic is

y = a(x-h)^2 + k, where (h,k) is the vertex.

y = a(x-2)^2 + 5 , leaving us only with the a as an unknown, but we know the point (-8,15) lies on it, thus must satisfy our equation, so ...

15 = a(-8-2)^2 + 5
10 = 100a
a = 10/100 = 1/10

equation: y = (1/10)(x-2)^2 + 5

2.

for the y-intercept, let x = 0
we can visually see the would give us y = 6

for the x-intercept, let y = 0
then
2x^2 + x - 6 = 0
(2x - 3)(x + 2) = 0
x = 3/2 or x = -2

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Algebra

Find the equation of the quadratic function f whose graph is shown below. Ponts on the graph are (-3,-1)(-2,-4) f(x)=

2. ### college algebra

determine the quadratic function f whose graph is given. the vertex is (1,-3) y intercept is -2 please show work so i can see how this is done, thank you!

3. ### algebra 2

A quadratic equation can be written in vertex form or in standard form. Sometimes one form is more beneficial than the other. Identify which form would be more helpful if you needed to do each task listed below and explain why a.

4. ### Math

The graph of a quadratic function has vertex(3,-4) and passes through the point (4,1). Find the equation of the function in standard form. Rewrite the equation in general form. Could someone explain to me how to do this, just

1. ### algebra

For the quadratic function f(x) = - x^2 +2x + 6, find the vertex and the axis of symmetry, and graph the function. Again, I need help with this as these are practice examples for an upcoming quiz and I stink at this part of

2. ### Algebra

Please Help Guys! 1) Why is f(x)=(3x+13)2+89 not the vertex form of f(x)=9x2+2x+1? A.The expression has a constant outside of the squared term. B. The expression is not the product of two binomials. C. The variable x has a

3. ### Math

A quadratic function has a vertex of (3,-6) and the point (-1,10) lies on the graph of the function. Write the function in standard form. If you could help me with this question, that would be great. Thanks in advance.

4. ### algebra 2

a quadratic equation can be written in vertex form or in standard form. sometimes one form is more beneficial than the other. identify which form would be more helpful if you needed to do each task listed below and explain why. a.

1. ### Algebra

For the given quadratic equation convert into vertex form, find the vertex, and find the value for x = 6. Show your work. y = -2x2 + 2x +2 -(1/2)y=x^2-x-1 (-1/2)y+1=x^2-x (-1/2)y+1=(x-1/2)^2-14 (-1/2)y=(x-1/2)^2-5/4

2. ### Algebra

Please help.! 1) Given the following three points, find by hand the quadratic function they represent. (0,6), (2,16), (3, 33) A. f(x)=4x2−3x+6 B. f(x)=4x2+3x+6 C. f(x)=−4x2−3x+6 D. f(x)=−4x2+21x+6 2) Given the following

3. ### math help!

f(x) is a quadratic function such that f(1) = 3 and f(5) = 3. Find the x coordinate of the vertex of the graph of f.

4. ### math

Algebraically analyze the graph of the function f(x)= -6x^2+5x+2 . Find the vertex, axis of symmetry, range, minimum or maximum value, increasing and decreasing intervals, and zeros. Write the Quadratic equation in standard form.