The answers to the questions

It is linear as the equation performs ax+by +c

y = 90.2x - 177670

Number of student to enroll 2011 is 3722

Explanation:

Linear is a straight line.Quadratic is a square which generates parabola.Quadratic formula is (ax)^2 + bx + c = 0.Linear formula is ax+bx + c = 0To  forecast time series data modelling can be used.To form a linear equation y = mx + c.After finding x is the required value , m is the intercept and C constant.X axis have years and Y axis has the value.To find number of students x is 90.2 * 2011 - 177670.The result comes to 3722.In Data analysis predictive modeling is the second phase.It is important because it helps in associating to variables.

Do the inverse operation