Question

Find a function whose graph is a parabola with vertex (1,-2) and that passes through the point (4,16).

Answer 1

Use the vertex formula for a parabola:

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

y = a(x-1)^2 -2 , now plug in x=4 and y=16 into this equation and solve for a. Then, you are done!

Answer 2

I tried this method out but it doesnt concord with the answer given in the answer key.

Answer 3

16 = a(4 - 1)² + (- 2)
16 = a(3)² - 2
16 = a(9) - 2
16 = 9a - 2
9a = 16 + 2
9a = 18
a = 18 / 9
a = 2
you should get this...

Answer 4

Then from there how would you obtain an equation?

Answer 5

so the function would be y=2(x-1)^2-2?

Answer 6

Thats the part i didnt get but here the answer key says 2x^2 -4x

Answer 7

maybe they just simplifyed the function?

Answer 8

Im not sure

Answer 9

im pretty sure thats what they did!

Answer 10

Yea i just realized that now thanks anyways stupidity at its finest haah (from my part)

Answer 11

its fine! good job tho! :)