Respuesta :
Answer:
y = (x − 2)² − 25
Step-by-step explanation:
Vertex form of a quadratic is:
y = a (x − h)² + k
where (h, k) is the vertex.
Given that h = 2 and k = -25:
y = a (x − 2)² − 25
And given that a point is (7, 0):
0 = a (7 − 2)² − 25
0 = 25a − 25
a = 1
Therefore, the equation is:
y = (x − 2)² − 25
Answer:
f(x) = x^2 - 4x - 21.
Step-by-step explanation:
Since the vertex is at (2, -25) we can write the vertex form as:
y = f(x) = a(x - 2)^2 -25
Given the x-intercept ( 7, 0), x = 7 when y = 0, so substituting:
0 = a(7 - 2)^2 - 25
0 = 25a - 25
giving a = 1.
So our equation is f(x) = (x - 2)^2 - 25.
Converting to standard form
f(x) = x^2 - 4x + 4 - 25
f(x) = x^2 - 4x - 21.