Question 73783
SLOPE=(Y2-Y1)/(X2-X1) OR
SLOPE=(4-3)/(2-1)=1/1=1 FOR THE SLOPE.
NOW SUBSTITUTE 1 FOR THE SLOPE(M) & ONE SET OF (X,Y) VALUES IN THE LINE EQUATION Y=mX+b & SOLVE FOR THE Y INTERCEPT (b)
3=1*1+b
3=1+b
b=3-1 
b=2 THE Y INTERCEPT
THUS THE EQUATION OF THIS LINE IS
Y=X+2
ANOTHER POINT ON THIS LINE WOULD BE (4,6).
GRAPH FOLLOWS
{{{ graph( 300, 200, -6, 5, -10, 10, y = x +2) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, y = x +2).