Question

If I have the x-intercepts (-10,0) and (10,0) and the vertex (0,12), what would the equation of the parabola be in the form of y=A(x-h)^2+k?

Answer 1

A determines if it opens up or down, in this case down.

Answer 2

I know its down by plotting the vertex and x ints. this means A is less than 0

Answer 3

But what is the equation? Where do the coordinates fit in?

Answer 4

Is anyone going to help me?

Answer 5

plot the point first

Answer 6

a parabola is a "U" shape

Answer 7

Isn't it inverted though?

Answer 8

It opens down

Answer 9

whats the answer choices I could solve it in 1 minute with them

Answer 10

\(\large\tt \begin{align} \color{black}{\color{blue}{\text{vertex(h,k)=(0,12),x intercepts (-10,0) and (10,0)}}\\~\\
\color{blue}{\text{u have to find the value of "a" here}}\\~\\
y=a(x-h)^2+k\\~\\
y=a(x-0)^2+12\\~\\
y=ax^2+12\\~\\
\color{blue}{\text{now put any one value of x intercept}}\\~\\
y=ax^2+12\\~\\
0=a(-10)^2+12\\~\\
a=\dfrac{-12}{100}\\~\\
a=\dfrac{-3}{25}\\~\\
\color{blue}{\text{equation of parabola}}\\~\\
y=a(x-h)^2+k\\~\\
y=\dfrac{-3}{25}x^2+12
}\end{align}\)