Determine the equation of the quadratic function with vertex ( 2 , 4 ) (2,4) and passing through the point ( 0 , − 8 ) (0,-8)

Question

 i need to be able to write an equations with the numbers given 

Answer 1

y=a(x-h)²+k where (h,k) is the vertex which is (2,4)

y=a(x-2)²+4

point (0,-8)

substitute these coordinates for x and y and solve for "a"

-8=a(0-2)²+4

-8=a(-2)²+4

-8=a(4)+4

-8-4=a(4)

-12=a(4)

a=-12/4

a=-3

y=-3(x-2)²+4