what is the linear function y=mx+c if points (-1,6) and (2,15) are on the graph of function?

To determine the linear function, we'll apply the
following formula:

y - y1 = m(x - x1), where m is the slope
of the line and (x1,y1) are the coordinates of one of two given
points.

m =
(y2-y1)/(x2-x1)

Let x1 = -1 , y1 = 6 , x2 = 2 , y2 =
15

m = (15-6)/(2+1)

m =
9/3

m = 3

We'll plug in the
values of m and x1 and y1 into the formula that gives the equation of the
line.

y - 6 = 3(x + 1)

We'll
put the equation of the line into the requested slope intercept form. For this reason,
we'll have to isolate y to the left side.

y - 6 = 3x +
3

y = 3x + 3 + 6

y = 3x +
9

The requested equation of the line is y =
3x + 9.