Question 118844
1. a newly-started high school hopes to enroll 80 students in its first year and to increase enrollment by 40 students per year over the next five years.
Let y = no. of students
Let x = no. of years
:
y = 40x + 80; on the initial opening of the school x=0
:
Plot it from x = 0 to x = 5:
 x | y
-------
 0 | 80
 1 | 120
 5 | 280
:
{{{ graph( 300, 200, -2, 5, -20, 300, 40x + 80) }}}
:
Negative values for x are not valid since the school did not exist before x=0
Same with negative values for y, negative students
(However, the existence of negative students is a debatable point)
:
:
5. temperature on the Fahrenheit scale is a linear function of temperature on the Celsius scale. Ten degrees Celsius equals 50 degrees Fahrenheit, and 25 degrees Celsius equals 77 degrees Fahrenheit.
:
Recall the formula for converting temp: F = {{{9/5}}}C + 32
:
Let x = C, and y = F
Plotting table  using the given values:
 x | y
-------
10 | 50
25 | 77
:
{{{ graph( 300, 200, -50, 100, -50, 220, (9/5)x+32) }}}
:
Negative values are certainly valid here, It's interesting that at -40 degrees
Celsius and Fahrenheit are equal
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Did this help, any questions?