SOLUTION: In January, your ceramics class begins with 12 students. In every month after January, three new students join and one student drops out. (a) Write a linear equation to model th

Algebra ->  Linear-equations -> SOLUTION: In January, your ceramics class begins with 12 students. In every month after January, three new students join and one student drops out. (a) Write a linear equation to model th      Log On


   



Question 461511: In January, your ceramics class begins with 12 students. In every month after January, three new students join and one student drops out.
(a) Write a linear equation to model the situation.
(b) Graph a model
(c) Predict the size of your ceramics class in May and June.
Need help with a and c and then will try my hand at the graphing.

Answer by graphmatics(170) About Me  (Show Source):
You can put this solution on YOUR website!
Let y be the number of students in a given month. Let x be the number of months with x = 1 being January.
then (x-1)*3 is the number of new students and (x-1) is the number of student drop outs.
Then
y = 12 + (x-1)*3 - (x-1)
Lets simplify this as y = m*x+b
So
y = 12 + (x-1)*3 - (x-1)
y = 12 + 3*x -3 -x +1
y = 2*x + 10
Here is the graph of the linear equation that models the situation
+graph%28+300%2C+300%2C+-2%2C+16%2C+-2%2C+30%2C+2%2Ax%2B10%29+
If in January x = 1 then in May x = 5. So the expression of the Linear Equation when x = 5 is
y = 2*5 + 10
y = 20
and in June x = 6 so
y = 22