Write the standard form equation of the parabola that passes through (20,−40),if the vertex at the origin and the axis of symmetry is vertical.

y = -0.1x^2

Step-by-step explanation:

Start out with vertex form

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

The vertex at the origin

Therefor (h, k) = (0, 0)

y = ax^2

use point (20, -40) to find a

-40 = a(20^2)

-40 = a(400)

Divide both sides by

400

-0.1 = a

Therefor

y = -0.1x^2

This is standard form with a = -.01 and both b and c equal to zero

if a = 1,   and b = 2, then the answer is 47.99999999. if you round that to the nearest whole number, the answer is 48.

the total estimated nappy use.=10,500,000

step-by-step explanation:

given that on an average the average baby uses 3528 napkins.

in a particular year 2014, the number of births were 299697 in new south wales.

rounding off the number of births to the nearest hundred thousand we have

no of birtsh = 300000

also rounding off the average usage to nearst thousand we get

average use of a baby = 3500

hence total number of nappy estimated to be used = 3500x300000

= 10,500,000

answer is 10,500,000 nappies