Vertex (1,2) point (2,-5)

Question

how to write the equations of each parabola in vertex forms 

Answer 1

f(x) = a(x - h)² + k

f(x) = a(x - 1)² + 2

-5 = a(2 - 1)² + 2

 

You can solve for a.

Answer 2

The vertex form of the equation of a parabola is y = A(x-h)² + k, where (h,k) is the vertex.

 

So, we have y = A(x-1)² + 2

 

Since (2,-5) is on the graph, -5 = A(2-1)² + 2

 

                                          -5 = A + 2

 

                                           A = -7

 

So, y = -7(x-1)² + 2