Question 955849

I can not find r my answer seems wrong
(2,8)(r-4) m=-3 please show me step by step
<pre>With a slope, or m of - 3, and points, (2, 8) and (r, -4), we use the slope formula: {{{m = (y[1] - y[2])/(x[1] - x[2])}}} to get:
{{{- 3 = (8 - - 4)/(2 - r)}}}
{{{- 3 = (8 + 4)/(2 - r)}}}
{{{- 3 = 12/(2 - r)}}}
{{{- 3(2 - r) = 12}}} ------ Cross-multiplying
- 6 + 3r = 12
3r = 12 + 6
3r = 18
{{{r = 18/3}}}, or {{{highlight_green(r = 6)}}}