Question 733674
In general, the slope intercept form assumes the formula: {{{y= mx +b}}}; so, your equation is already in the slope intercept form 

{{{y=-3x-6}}}.....the slope is {{{m=-3}}} and {{{y-intercept=-6}}}

you are given a point ({{{x}}}, {{{y}}})=({{{-1}}}, {{{5}}}) and we can check if this point lies on given line {{{y=-3x-6}}}


{{{y=-3x-6}}}...plug in coordinates of given point {{{x=-1}}} and {{{y=5}}}


{{{5=-3(-1)-6}}}

{{{5=3-6}}}

{{{5=-3}}}...it's not true; so, this point does not lie on a line


{{{ drawing(500, 500, -10, 10, -10, 10,circle(-1,5,0.1),locate(-1.6,5,"(-1,5)"),graph( 500, 500, -10, 10, -10, 10, -3x-6)) }}}