Answer:
[tex]\large\boxed{y=-\dfrac{1}{5}x+5}[/tex]
Step-by-step explanation:
[tex]\text{Let}\\\\k:y=m_1x+b_1\\\\l:y=m_2x+b_2\\\\\text{then}\\\\k\ \perp\ l\iff m_1m_2=-1\to m_2=-\dfrac{1}{m_1}\\\\k\ ||\ l\iff m_1=m_2[/tex]
[tex]\text{We have}\ y=5x-1\to m_1=5.\\\\\text{therefore}\ m_2=-\dfrac{1}{5}.\\\\y=-\dfrac{1}{5}x+b\\\\\text{Substitute the coordinaes of the given point (15, 2):}\\\\2=-\dfrac{1}{5}(15)+b\\\\2=-3+b\qquad\text{add 3 to both sides}\\\\5=b\to b=5\\\\\bold{FINALLY:}\\\\y=-\dfrac{1}{5}x+5[/tex]
