Just put your x to equation and you get y.
Ex.
y = -3(-4)+4
y = 12 + 4 = 16
Answer:
(4,1)
Step-by-step explanation:
The vertex of the quadratic can be found using -b/2a. The vertex is the point (-b/2a, f(-b/2a)).
To find the x coordinate of the quadratic, define its a,b, and c. The quadratic has a = 2, b=-16, and c=31. Then -b/2a is -(-16)/2(2) = 16/4 = 4.
To find the y-coordinate, input the x=4 and solve for y.

The vertex is (4,1).
D
The cable increases by 20 in addition to the length of cable needed
Answer:
a) 412 have a brother or sister in the school
b) 242 are girls
c) 339 are 13 years old or under
Step-by-step explanation:
Part a:
515 x 80%
412
Part b:
515 x 47%
242
Part c:
515 x 66%
339