standard_description: Construct a function to model a linear relationship between two quantities. Determine the rate of change and initial value of the function from a description of a relationship or from two (x, y) values, including reading these from a table or from a graph. Interpret the rate of change and initial value of a linear function in terms of the situation it models, and in terms of its graph or a table of values.
problem_activity: Problem 1
Determine the rate of change in each situation. Then describe the relationship using function language (for example, ____ is a function of ____ because _____.)
a.
{"table": [{"_attributes": {"class": ["table", "table-bordered"], "style": "width: 100%;"}, "tbody": [{"tr": [{"th": [{"_attributes": {"scope": "row"}, "_value": "Amt of watermelon in pounds,", "span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$x$$"}]}], "td": [{"_attributes": {"style": "text-align: center;"}, "_value": "0"}, {"_attributes": {"style": "text-align: center;"}, "_value": "0.25"}, {"_attributes": {"style": "text-align: center;"}, "_value": "0.5"}, {"_attributes": {"style": "text-align: center;"}, "_value": "1.5"}, {"_attributes": {"style": "text-align: center;"}, "_value": "2"}, {"_attributes": {"style": "text-align: center;"}, "_value": "3"}, {"_attributes": {"style": "text-align: center;"}, "_value": "5"}]}, {"th": [{"_attributes": {"scope": "row"}, "_value": "Cost of watermelon in dollars,", "span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$y$$"}]}], "td": [{"_attributes": {"style": "text-align: center;"}, "_value": "0"}, {"_attributes": {"style": "text-align: center;"}, "_value": "0.35"}, {"_attributes": {"style": "text-align: center;"}, "_value": "0.70"}, {"_attributes": {"style": "text-align: center;"}, "_value": "2.10"}, {"_attributes": {"style": "text-align: center;"}, "_value": "2.80"}, {"_attributes": {"style": "text-align: center;"}, "_value": "4.20"}, {"_attributes": {"style": "text-align: center;"}, "_value": "7.00"}]}]}]}]}
b.
$${d=25t}$$
, where
$$d$$
is distance in miles and
$$t$$
is time in hours
c.    Giovanni can decorate
$$2$$
cakes,
$$c$$
, every
$$5$$
hours,
$$h$$
.
Problem 2
Determine the starting or initial output value in each situation.
a.
{"table": [{"_attributes": {"align": "Center", "class": ["table", "table-bordered"], "style": "width:80%"}, "tbody": [{"tr": [{"td": [{"_attributes": {"style": "background-color:#eeeeee"}, "strong": [{"_value": "Distance traveled in cab in miles,", "em": [{"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$x$$"}]}]}]}, {"_attributes": {"style": "text-align:center"}, "_value": "0"}, {"_attributes": {"style": "text-align:center"}, "_value": "1"}, {"_attributes": {"style": "text-align:center"}, "_value": "3"}, {"_attributes": {"style": "text-align:center"}, "_value": "4"}]}, {"td": [{"_attributes": {"style": "background-color:#eeeeee"}, "strong": [{"_value": "Cost of cab ride in dollars,", "em": [{"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$y$$"}]}]}]}, {"_attributes": {"style": "text-align:center"}, "_value": "2.50"}, {"_attributes": {"style": "text-align:center"}, "_value": "4.75"}, {"_attributes": {"style": "text-align:center"}, "_value": "9.25"}, {"_attributes": {"style": "text-align:center"}, "_value": "11.50"}]}]}]}]}
b.
{"table": [{"_attributes": {"align": "Center", "class": ["table", "table-bordered"], "style": "width:80%"}, "tbody": [{"tr": [{"td": [{"_attributes": {"style": "background-color:#eeeeee"}, "strong": [{"_value": "Distance traveled in cab in miles,", "em": [{"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$x$$"}]}]}]}, {"_attributes": {"style": "text-align:center"}, "_value": "1"}, {"_attributes": {"style": "text-align:center"}, "_value": "2"}, {"_attributes": {"style": "text-align:center"}, "_value": "4"}, {"_attributes": {"style": "text-align:center"}, "_value": "5"}]}, {"td": [{"_attributes": {"style": "background-color:#eeeeee"}, "strong": [{"_value": "Cost of cab ride in dollars,", "em": [{"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$y$$"}]}]}]}, {"_attributes": {"style": "text-align:center"}, "_value": "4.50"}, {"_attributes": {"style": "text-align:center"}, "_value": "7.00"}, {"_attributes": {"style": "text-align:center"}, "_value": "12.00"}, {"_attributes": {"style": "text-align:center"}, "_value": "14.50"}]}]}]}]}
c.
$${p=16d+20}$$
where
$$p$$
is the total number of pages read in a book and
$$d$$
is the number of days
Problem 3
The function formula below shows the relationship between temperature in degrees Fahrenheit and degrees Celsius. °F is a function of °C.
$${F=\frac{9}{5}C+32}$$
a.   Determine what 28°C is in °F.
b.   Determine what 23°F is in °C.


aligns: yes