the unit rate is the same slope
to calculate the slope we only need two points and this formula
[tex]m=\frac{y2-y1}{x2-x1}[/tex]
where (x2,y2) is a right point from (x1,y1)
I can take two any points for this case i will use (1,5) and (3,15)
we can look (3,15) is right from (1,5) so (3,15) is (x2,y2)
now, replacing
[tex]\begin{gathered} m=\frac{15-5}{3-1} \\ \\ m=\frac{10}{2} \\ \\ m=5 \end{gathered}[/tex]
4. how do you know?
the unit rate is the slope, so by formula we can find it
and 5 is the change per unit, we can notice when add a unit of days the big smiles incresses by 5 everytime
