Question 317648
a) Parallel lines have identical slopes.
 {{{m1=m2=-7/8}}}
Use the slope-intercept form of a line,
{{{y=mx+b}}} 
{{{y=-(7/8)x+b}}}
Use the point to solve for b.
{{{15=-(7/8)(56)+b}}}
{{{b=15+49}}}
{{{b=64}}}
{{{highlight(y= -(7/8)x+64 )}}}
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Perpendicular lines have slopes that are negative reciprocals,
{{{m1*m2=-1}}}
{{{-(7/8)*m2=-1}}}
{{{m2=8/7}}}
Use the point to solve for b.
{{{15=(8/7)(56)+b}}}
{{{b=15-64}}}
{{{b=64}}}
{{{highlight(y= (8/7)x-49 )}}}
.
.
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{{{drawing(300,300,-10,70,-40,40,grid(1),circle(56,15,1.5),graph(300,300,-10,70,-40,40, 24-(7/8)x,-(7/8)x+64 ,(8/7)x-49 ))}}}