HELP ASAP FOR BRAINLIEST:
What is the equation of a quadratic function with roots -1 and -7 and a vertex at (-4, 7)?
Please show step by step how you did this, providing the original formula and then the formula with numbers added in. THANK YOU!

Respuesta :

Answer: y = -14/9(x + 4)^2 + 7

Step-by-step explanation:

The given roots of the quadratic function is (-1, -7)

The vertex is at (-4, 7)

The formula is

y = a(x - h)^2 + k

The vertex is (h, k)

Comparing with the given vertex, (-4, 7), h = -4 and k = 7

Substituting into the formula

y = a(x - h)^2 + k, it becomes

y = a(x - - 4)^2 + 7

y = a(x + 4)^2 + 7

From the roots given (-1, -7)

x = -1 and y = -7

Substituting x = -1 and y = -7 into the equation,

y = a(x + 4)^2 + 7, it becomes

-7 = a(-1+4)^2 + 7

-7 = a(3^2 ) + 7

- 7 = 9a + 7

-7-7 = 9a

9a = -14

a = -14/9

Substituting a = - 14/9 into the equation, it becomes

y = -14/9(x + 4)^2 + 7