Answer:
Option B: 
Step-by-step explanation:
The parabola has its concavity downwards, so we need a function in the model:

With a negative value of 'a'
The vertex is (0,0), so we have that:


The x-coordinate of the vertex is given by the equation:



So we have a function in the model:

With a < 0
The only option with this format is B:

First, i put the equation in y=mx+b by dividing 2, since its 2y. since it’s perpendicular we’re talking about you switch the sides (opposite reciprocals). the rest should be self explanatory.
Answer:
C
Step-by-step explanation:
Its C because its x (a variable) and is costanly changing
Answer:
let x =the original price
then 116x/100=$39.32
116x=100×39.32
116x=3932
divide both sides by 116
116x/116=3932/116
x=33.89655
(2dp)
x=33.90
N= 13*c+8
n=15*c
15c=13c+8
15c-13c=8
2c=8
c=8:2
c=4 children
n= 15*4=60 notebooks