21. write the equation of the line that is
perpendicular to y = -x - 11 and passes through
the point (9,2).

When a line is given in the form

The slope of the line is m. So, in this case, the slope of is -1.

Given a slope , you find the slope of a perpendicular line by imposing

So, if the given line has slope -1, a perpendicular line has slope given by

and thus

So, we want a line with slope 1 and passing through (9,2). Using the fomula

we get

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