Question 82419
First solve for y:

{{{x-y=3}}}


{{{-y=3-x}}} Subtract x from both sides


{{{y=-3+x}}} Multiply both sides by -1 to make y positive


So we have


{{{y=x-3}}}


So it is now in {{{y=mx+b}}} form where m is the slope and b is the y intercept. Since {{{b=-3}}} the y-intercept is (0,-3) (b is always the y coordinate of the y-intercept). Notice if we plug in x=0 we get


{{{y=0-3}}}


{{{y=-3}}}


This verifies our answer.


Also notice if we graph {{{y=x-3}}} we get



{{{ graph( 300, 200, -5, 5, -5, 5, x-3) }}} 


and you can see that the y-intercept is (0,-3)