Question 752564
You could use the point-slope form for a line.


Instead, here is the use of slope-intercept form.


{{{y=-(1/2)x+b}}}, where b is the y intercept.
You were given the x intercept point of x=4 and y=0.  Putting these into our equation gives us:
{{{0=-(1/2)*4+b}}}
{{{0=-2+b}}}
{{{b=2}}}.


The equation desired then is {{{highlight(y=-(1/2)x+2)}}}