Answer:
[tex]P(w)=0.2w+1[/tex]
Step-by-step explanation:
Let is call [tex]P[/tex] the price of the cereal box, and [tex]w[/tex] its weight, then the linear equation of the price [tex]P(w)[/tex] as a function of weight [tex]w[/tex] will be
[tex]P(w)=mw+b[/tex],
where [tex]m[/tex] is the slope of the linear equation, and [tex]b[/tex] is the y-intercept.
We find [tex]m[/tex] by evaluating the rise/ run of the linear equation:
[tex]m= \frac{ \Delta rise}{ \Delta run} = \frac{ \Delta price}{ \Delta weight} =\frac{5-3}{20-10} =\frac{2}{10} \\\\\boxed{m=0.2}[/tex]
thus we have
[tex]P(w)+0.2w+b[/tex]
now we figure out [tex]b[/tex] from the point ($5, 20 ounces):
[tex]5=0.2(20)+b\\5=4+b\\\\\boxed{b=1}[/tex]
So finally we have the function
[tex]\boxed{P(w)+0.2w+1}[/tex]
which expresses the price of a box of cereal as a function of the number of ounces of cereal in the box