constant of proportionallity
finding rate of change from a graph
find x and y
find your independent and dependent variables. then you wright your equation. example; your new job is at the custom t shirt shop where t shirts are printed to order custom t shirts charge 8.00 for a shirt plus one time set up fee of 15.00. so the y is cost and x is number of shirts because the cost depends on number of shirts. after that you write your equation 8x+15 so how this becomes your equation is that 8 is the cost and you have to multiply it by the number of shirts and the $15 is the fee because its the one time set up fee
create your table
x is the number of shirts and y is the cost. you see that 0 dollars equals 15 dollars because of the fee. now if you by one you have to multiply 8 by then number given then add 15 for the fee.
RATE OF CHANGE
build your graph
your y is cost and your x is the number of shirts you buy. on the bottom you put number of shirts and on the side you would put the cost. you put number of shirts given and number the graph to the side for the cost. then you would just start putting your dots on the coordinates. after that you would just line up your graph.