6 isn't a point. Do you mean... x = 6?
EDIT: For the point (1,6)
y = x^{2} + 3x + 2
y' = 2x + 3
So if it's x = 1:
y' = 2(1) + 3 = 5
Now you use that y-y1 formula:
y - y_{1} = m(x-x_{1})
m = 5 from what we've figured out, x1 is 1, y1 is 6.
So then:
y - 6 = 5(x-1)
Rearrange:
y = 5x +1...