What are you asking cause I do not get it
Answer:
k=9
Step-by-step explanation:

Answer:
vertex = (0, -4)
equation of the parabola: 
Step-by-step explanation:
Given:
- y-intercept of parabola: -4
- parabola passes through points: (-2, 8) and (1, -1)
Vertex form of a parabola: 
(where (h, k) is the vertex and
is some constant)
Substitute point (0, -4) into the equation:

Substitute point (-2, 8) and
into the equation:

Substitute point (1, -1) and
into the equation:

Equate to find h:

Substitute found value of h into one of the equations to find a:

Substitute found values of h and a to find k:

Therefore, the equation of the parabola in vertex form is:

So the vertex of the parabola is (0, -4)
Answer:
Step-by-step explanation:
We are told that the perimeter is 48 = 2L + 2W. This reduces to
24 = L + W. Next, substitute, one by one, the 3 widths 10 cm, 3.6 cm and w cm:
a) If W = 10 cm, 24 = L + W becomes 24 = L + 10, or L = 14 cm
b) If W = 3.6 cm, 24 = L + W becomes 24 = L + 3.6, or L = 20.6 cm
c) If W = w, 24 L + W becomes 24 = L + w, so that L = (24 - w) cm
The most important thing that you have to know is that all angles in a triangle equals 180°