Question 802184
Knowing the slope and a point on the line, you can formulate the equation for the line.


Slope is {{{(vertical change)/(horizontal change)}}}.
Two points, (u,v) and (p,q) have a slope {{{m=(v-q)/(u-p)}}}.


Imagine a general point, (x,y) on a line and a known point, (u,v) on the line.
Slope would be {{{m=(y-v)/(x-u)}}}.  This is equivalent to:
{{{y-v=m(x-u)}}}


You have a specific example, {{{m=-5}}} and a point (2,8) on the line.  The equation for this line is {{{highlight(y-8=-5(x-2))}}}, corresponding exactly to the form just derived.  This equation is in point-slope form.  You can change into slope-intercept form:  Solve for y and simplify.
{{{y=-5(x-2)+8}}}
{{{y=-5x+10+8}}}
{{{highlight(y=-5x+18)}}}