The slope of the line is 3 therefore we know that the line will be in the form y= 3x + c
Now to find c, the y-intercept, we will substitute our set of values, (-2,6), into the equation to get-
6= 3(-2) + c
=>6= -6 + c
=>6+6= c
=>12= c
Therefore, the equation of the line is
y= 3x + 12