I think I know the concept just a little confused on the answer.

Question

zarkam21 · Answer

attachment

mathmale · Answer

When you know the VERTEX of a parabola, the best formula for the equation of the parabola to use is, appropriately enough, the "vertex formula:"$$y-k=a(x-h)^2$$ for a vertical parabola.

mathmale · Answer

You are given the coordinates of the vertex AND the coordinates of one point on the graph of the parabola.  Substitute these numerical values into the equation given abov e and then determine the value of the constant coefficient, 'a.'

mathmale · Answer

Since the vertex is at (-2,-1), h=-2 and k=-1.

Since the given point is on the curve, x=-1 and y=1.

mathmale · Answer

This is all the info you need with which to calculate the coefficient 'a.'

zarkam21 · Answer

1-(-2)=a(-1-(-1))^2

zarkam21 · Answer

I don't need to calculate anything I just need to write the equation

mathmale · Answer

Try finding a now.

We will check your answer once you have "a."

mathmale · Answer

You do need to simplify the equation you've typed in.  From it we will obtain the general equation (in vertex form) for this parabola.

zarkam21 · Answer

Okay so the equation i typed in, is it correct so far teacher?

mathmale · Answer

We will check your equation once you've finished finding "a."

mathmale · Answer

$$y-k=a(x-h)^2$$ is (again) the most general form of the vertex equation.
Subst. the values of h, k and a.

What equation do you obtain by doing so?

mathmale · Answer

Solve for a:  1-(-2)=a(-1-(-1))^2

zarkam21 · Answer

3-a(0)^2=0

mathmale · Answer

So a=0?  Unfortunately, that's not possible.

mathmale · Answer

$$1-(-2)=a(-1-(-1))^2$$     Looks like there's an arithmetic problem here.

mathmale · Answer

$$y-k=a(x-h)^2$$

mathmale · Answer

since the vertex is at (-2,-1), subst. -1 for k and -2 for h.  Then$$y-(-1)=a(x-(-2))^2$$

mathmale · Answer

Now the given point is (-1,1).  Subst. -1 for x and 1 for y.  Yes, I think you've already done these things, but let's be sure our equation for a is correct.

zarkam21 · Answer

Okay lets make sure

mathmale · Answer

I'm getting the same result as you:  a=0.  That could not possibly be true.  Can you move on to another problem or do you have to type in some answer for this one first?

zarkam21 · Answer

No its a assignment I can move on

mathmale · Answer

I'd suggest you do that.  I'm trying to find a solution to this problem in a different way.

zarkam21 · Answer

Okay, Meanwhile I will try to work on the other problems, thanks

zarkam21 · Answer

Anything yet?

zarkam21 · Answer

@mathmale