## ciara_chap3 3 years ago Suppose a parabola has vertex (5, –3) and also passes through the point (6, 1). Write the equation of the parabola in vertex form. A. y = (x – 5)2 – 3 B. y = 4(x – 5)2 – 3 C. y = 4(x + 5)2 – 3 D. y = 4(x – 5)2 + 3

1. ParthKohli

Play smart.

2. ParthKohli

Eliminate the choices that DON'T have the vertex = (5,-3).

3. ciara_chap3

i know its either a or b but from their i dont know what to do.

4. ciara_chap3

just kidding i thought it was -5. so it has to be c since thats the only one with +5

5. ParthKohli

You're perfectly right. Now check if (6,1) is also a point in both the choices.

6. ParthKohli

No, it's A or B.

7. ciara_chap3

a and b both have -5 its +5

8. ParthKohli

The standard form is this:$\rm y = a(x - h)^2 + k$(h,k) is the vertex.

9. ParthKohli

It's either A or B. Get it now?

10. ciara_chap3

yeah i get it now. but how do i check if (6,1) is also a point?

11. ParthKohli

You plug in 6 for x and 1 for y, then check if both sides are equal.