Question 22433
y=mx+b
The point (2,1) gives you an "x" and a "y" value
and you are also given the "m" value.  Substitute
to get 1 = (1)(2)=b
       1 = 2b
       b = 1/2
The equation is y = x+1/2
Now, put that in standard form which is ax + by = c
Multiply (y=x+1/2) thru by "2" to get:
  2y= 2x + 1
Write this as 
2x+(-2y)= -1
That is the equation in standard form.

Cheers,
Stan H.