Well, from the info given, you cannot automatically put it into slope intercept form. You have to put it into point slope form first and then convert it.
Point slope form looks like this: y - y1 = m(x - x1)
Now, with the info it looks like this: y - (-2) = -3(x - 1)
Now you distribute and change the - (-2) to +2 (because subtracting a negative is the same as adding a positive) and you get: y + 2 = -3x - 3
Now, you subtract 2 to get y by itself (we are converting now)
y = -3x - 5
Hope this helps!