Question 919309
the standard slope-intercept form for an equation of a line is 
{{{y = highlight_green(m)x + highlight(b)}}}  where m is the slope and b the y-intercept.  
-x+2y+2=0 0r y = (1/2)x - 1,  m = 1/2
.........New Line(Slope also  1/2, Lines parallel have same slope)
 (a,1) and 
(2,2)  m ={{{(y[1] - y[2])/(x[1] - x[2] )}}} = {{{-1/(a-2) = 1/2}}}, {{{a-2 = -2}}},{{{ highlight_green(a=0)}}}