Insert the coordinates into the formula with their CORRECT signs. Remember, in the Point-Slope Formula, <em>y - y₁ = m(x - x₁)</em><em>,</em><em> </em>all the negative symbols give the OPPOSITE term of what they really are. In addition, I recall that perpendicular lines have OPPOSITE <em>MULTIPLICATIVE INVERSE </em>[<em>RECIPROCAL</em>] <em>rate of changes</em> [<em>slopes</em>], so -4 really should be replaced with ¼, but if your assignment says otherwise, then this is the answer.
<span>The right answers would be B (7 miles after marker 58) and C (7 miles before marker 58). The problem doesn't say if the rest area is going to be built 7 miles before milepost 58 or 7 miles after it.</span>
