Find A From A Point And Vertex

Jack wants to know how high the soccer ball will get if he kicks it straight up in the air. Which one are we looking for?

• x at vertex

• y at vertex

• positive zero

Nancy is trying to find how many seconds it will take a golf ball to get to its highest point after being hit on the golf course. Which one are we looking for?

• x at vertex

• y at vertex

• positive zero

Sally threw a ball in the air. Sally’s friend wanted to find out how high the ball got given that it took 1 second to get to its highest point.

Which one are we looking for?

• x at vertex

• y at vertex

• positive zero

Ray found the maximum height of a basketball thrown from half court to be 21 feet and wants to know how long it took to get there.

Which one are we looking for?

• x at vertex

• y at vertex

• positive zero

How do I find… The time it takes to get to the highest point? (circle all that apply)

• use the axis of symmetry formula

• use the Maximum function, read x

• Use the Maximum function, read y

• use the Zero function

• Use the Quadratic Formula

How do I find…

The highest point?

(circle all that apply)

A: Use the Maximum function, read x

B: Use the Maximum function, read y

C: Use the axis of symmetry formula, plug back into equation

D: Use the Quadratic Formula

• Use the Maximum function, read x

• Use the Maximum function, read y

• Use the axis of symmetry formula, plug back into equation

• Use the Quadratic Formula

Lily wants to know how long her toy rocket will be in the air after she lights the fuse to launch it from a 1.5-foot launch pad.

Which one are we looking for?

• x at vertex

• y at vertex

• positive zero

Bill is wondering how long it will take a football to hit the ground after Tom Brady throws it during practice.

Which one are we looking for?

• x at vertex

• y at vertex

• positive zero

Write a quadratic equation given the x intercepts and one other point.

Step 2: Find a.

Now that you know that the factors are (x-6) and (x-8), you must find a. Plug the coordinates of the vertex (7, 1) in for x and y and solve for a.

y = a(x-6)(x-8)

What is the value of a?

• a = 1

• a = -1

• a = 7

• a = -7

Write a quadratic equation in vertex form given the vertex and another point.

1. Substitute the coordinates of the vertex (1, -4) in for h and k.

Vertex form: y=a(x-h)²+k

• (x+1)²-4=y

• (x-1)²-4=y

• (x + 1)(x - 3)=y

• x2 +2x - 3=y