Question 135815
The graph of a line is a set of points.  If a point is on the line, then the values of the x- and y-coordinates substituted for x and y in the equation will make the equation a true statement.


For example, take the line {{{2x-y=3}}}.  The point (4,5) is on the line because {{{2(4)-5=8-5=3}}}, so substituting 4 for x and 5 for y makes the equation a true statement.  On the other hand, the point (1,1) is not on the line, because {{{2(1)-1=2-1=1<>3}}}, so substituting 1 for x and 1 for y makes the equation a false statement.


The x-intercept is a point of the form (x,0), because y is zero anywhere on the x-axis.  So the question becomes: What value does x have to be so that the equation is a true statement when {{{y = 0}}}?


The procedure is to substitute 0 for y in the equation and then solve the resulting single variable equation for x.